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Complementary and Alternative Medicine - Cam

Search Health Information    Vitamin B6

Vitamin B6

Uses

What Are Star Ratings?

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.

2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.

1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

This supplement has been used in connection with the following health conditions:

Used for Why
3 Stars
Anemia
2.5 to 25 mg daily for three weeks, then 1.5 to 2.5 mg per day as maintenance therapy
Vitamin B6 deficiency can contribute to anemia, supplementing with this vitamin may restore levels and improve symptoms.

Deficiencies of iron , vitamin B12 , and folic acid are the most common nutritional causes of anemia.1 Although rare, severe deficiencies of several other vitamins and minerals, including vitamin A ,2 , 3 vitamin B2 ,4 vitamin B6 ,5 , 6 vitamin C ,7 and copper ,8 , 9 can also cause anemia by various mechanisms. Rare genetic disorders can cause anemias that may improve with large amounts of supplements such as vitamin B1 .10 , 11

3 Stars
Anemia and Genetic Vitamin B6-Responsive Anemia
50 to 200 mg per day
Taking vitamin B6 may partially correct sideroblastic anemia, although they must be taken for life.

Sideroblastic anemia refers to a category of anemia featuring a buildup of iron-containing immature red blood cells (sideroblasts). One type of sideroblastic anemia is due to a genetic defect in an enzyme that uses vitamin B6 as a cofactor.12 , 13 Vitamin B6 supplements of 50 to 200 mg per day partially correct the anemia, but must be taken for life.14

3 Stars
Autism
30 mg daily per 2.2 lbs (1 kg) of body weight; doctor's supervision recommended 
Research shows that vitamin B6 can be helpful for autistic children.

Uncontrolled and double-blind research shows that vitamin B6 can be helpful for autistic children.15 , 16 , 17 In these trials, children typically took between 3.5 mg and almost 100 mg of B6 for every 2.2 pounds of body weight, with some researchers recommending 30 mg per 2.2 pounds of body weight. Although toxicity was not reported, such amounts are widely considered to have potential toxicity that can damage the nervous system; these amounts should only be administered by a doctor. One prominent researcher has suggested that vitamin B6 is better supported by research than is drug treatment in dealing with autism.18

3 Stars
Depression
20 mg twice daily
Oral contraceptives can deplete the body of vitamin B6, a nutrient needed for normal mental functioning. In such cases, vitamin B6 supplementation may improve mood.

Oral contraceptives can deplete the body of vitamin B6 , a nutrient needed for maintenance of normal mental functioning. Double-blind research shows that women who are depressed and who have become depleted of vitamin B6 while taking oral contraceptives typically respond to vitamin B6 supplementation.19 In one trial, 20 mg of vitamin B6 were taken twice per day. Some evidence suggests that people who are depressed—even when not taking the oral contraceptive—are still more likely to be B6 deficient than people who are not depressed.20

Several clinical trials also indicate that vitamin B6 supplementation helps alleviate depression associated with premenstrual syndrome (PMS),21 although the research remains inconsistent.22 Many doctors suggest that women who have depression associated with PMS take 100–300 mg of vitamin B6 per day—a level of intake that requires supervision by a doctor.

3 Stars
High Homocysteine (Folic Acid, Vitamin B12)
400 to 1,000 mcg of folic acid daily, 10 to 50 mg of vitamin B6 daily, and 50 to 300 mcg of vitamin B12 daily
Vitamin B6, folic acid, and vitamin B12 all play a role in converting homocysteine to other substances within the body and have consistently lowered homocysteine levels in trials.

Vitamin B6 , folic acid , and vitamin B12 all play a role in converting homocysteine to other substances within the body. By so doing, they consistently lower homocysteine levels in research trials,23 , 24 , 25 a finding that is now well accepted. Several studies have used (and some doctors recommend) 400–1,000 mcg of folic acid per day, 10–50 mg of vitamin B6 per day, and 50–300 mcg of vitamin B12 per day.

Of these three vitamins, folic acid supplementation lowers homocysteine levels the most for the average person.26 , 27 It also effectively lowers homocysteine in people on kidney dialysis.28 In 1996, the FDA required that all enriched flour, rice, pasta, cornmeal, and other grain products contain 140 mcg of folic acid per 3½ ounces.29 This level of fortification has led to a measurable decrease in homocysteine levels.30 However, even higher levels of food fortification with folic acid have been reported to be more effective in lowering homocysteine,31 suggesting that the FDA-mandated supplementation is inadequate to optimally protect people against high homocysteine levels. Therefore, people wishing to lower their homocysteine levels should continue to take folic acid supplements despite the FDA-mandated fortification program.

3 Stars
Morning Sickness
10 to 25 mg three times daily
In two double-blind trials, supplementation with vitamin B6 significantly reduced the severity of morning sickness.

In two double-blind trials, supplementation with vitamin B6 (10 or 25 mg three times per day) significantly reduced the severity of morning sickness.32 , 33

3 Stars
Premenstrual Syndrome
100 to 200 mg per day on a regular basis
Many clinical trials show that taking vitamin B6 helps relieve PMS symptoms.

Many,34 , 35 , 36 , 37 , 38 though not all,39 clinical trials show that taking 50–400 mg of vitamin B6 per day for several months help relieve symptoms of PMS. A composite analysis of the best designed controlled trials shows that vitamin B6 is more than twice as likely to reduce symptoms of PMS as is placebo.40 Many doctors suggest 100–400 mg per day for at least three months. However, intakes greater than 200 mg per day can cause side effects and should never be taken without the supervision of a healthcare professional.

2 Stars
Age-Related Cognitive Decline
20 mg daily
There is evidence that supplementing with vitamin B6 (pyridoxine) may improve memory performance, especially in people who are deficient.

Vitamin B6 (pyridoxine) deficiency is common among people over age 65.41 A Finnish study demonstrated that approximately 25% of Finnish and Dutch elderly people are deficient in vitamin B6 as compared to younger adults. In a double-blind trial, correcting this deficiency with 2 mg of pyridoxine per day resulted in small psychological improvements in the elderly group. However, the study found no direct correlation between amounts of vitamin B6 in the cells or blood and psychological parameters.42 A more recent double-blind trial of 38 healthy men, aged 70 to 79 years, showed that 20 mg pyridoxine per day improved memory performance, especially long-term memory.43

2 Stars
Age-Related Cognitive Decline (Folic Acid, Vitamin B12)
Refer to label instructions
In a study of women with cardiovascular disease or related risk factors, supplementing daily with folic acid, vitamin B6, and vitamin B12 appeared to prevent age-related cognitive decline in those with low dietary intake.

In a study of female health professionals who had cardiovascular disease or cardiovascular disease risk factors, daily supplementation with folic acid (2.5 mg), vitamin B6 (50 mg), and vitamin B12 (1 mg) for 5.4 years had no effect on cognitive function. However, supplementation appeared to prevent age-related cognitive decline in the 30% of women who had low dietary intake of B vitamins.44

 

2 Stars
Asthma
100 to 200 mg daily
Vitamin B6 deficiency is common in asthmatics. Supplementing with the vitamin may decrease the frequency and severity of asthma attacks.

Vitamin B6 deficiency is common in asthmatics.45 This deficiency may relate to the asthma itself or to certain asthma drugs (such as theophylline and aminophylline ) that deplete vitamin B6.46 In a double-blind trial, 200 mg per day of vitamin B6 for two months reduced the severity of asthma in children and reduced the amount of asthma medication they needed.47 In another trial, asthmatic adults experienced a dramatic decrease in the frequency and severity of asthma attacks while taking 50 mg of vitamin B6 twice a day.48 Nonetheless, the research remains somewhat inconsistent, and one double-blind trial found that high amounts of B6 supplements did not help asthmatics who required the use of steroid drugs.49

2 Stars
Carpal Tunnel Syndrome
100 to 300 mg daily for no more than three months; 50 to 100 mg daily after that
Vitamin B6 deficiency is common in people with carpal tunnel syndrome, supplementing with the vitamin has reportedly relieved symptoms.

Some, but not all, studies have found vitamin B6 deficiency to be common in people with CTS.50 Supplementation with vitamin B6 has reportedly relieved the symptoms of CTS,51 but some researchers have not found this treatment to be beneficial.52 , 53

Several studies report that people with CTS are helped when given 100 mg of vitamin B6 three times per day.54 , 55 Although some researchers have found benefits with lesser amounts,56 , 57 , 58 , 59 using less than 100 mg taken three times per day for several months has often failed.60 , 61 , 62 Most doctors assume that people with CTS who respond to vitamin B6 supplementation do so because of an underlying deficiency. However, at least one group of researchers has found vitamin B6 to “dramatically” reduce pain in people with CTS who did not appear to be B6-deficient.63 Some doctors believe that B6 is therapeutic because it reduces swelling around the carpal tunnel in the wrist; this theory remains completely undocumented.

Very high levels of vitamin B6 can damage sensory nerves, leading to numbness in the hands and feet as well as difficulty in walking; supplementation should be stopped if these symptoms develop after beginning vitamin B6 supplementation. Vitamin B6 is usually safe in amounts of 200 to 500 mg per day,64 although occasional problems have been reported in this range.65 Higher amounts are clearly toxic.66 Any adult taking more than 200 mg of vitamin B6 per day for more than a few months should consult a doctor.

In order to be effective, vitamin B6 must be transformed in the body to pyridoxal-5’-phosphate (PLP). Some doctors have suggested that people who do not respond well to vitamin B6 supplements should try 50 mg of PLP three times per day. There is no clear evidence that using PLP provides any advantage in reducing symptoms of CTS.

2 Stars
Celiac Disease (Vitamin B12)
3 mg vitamin B6, 0.8 mg folic acid, and 0.5 mg vitamin B12
Daily supplementation with a combination of vitamin B6 (3 mg), folic acid (0.8 mg), and vitamin B12 (0.5 mg) have been shown to help relieve depression in people with celiac disease.
In one trial, 11 people with celiac disease suffered from persistent depression despite being on a gluten-free diet for more than two years. However, after supplementation with vitamin B6 (80 mg per day) for six months, the depression disappeared.67 Daily supplementation with a combination of vitamin B6 (3 mg), folic acid (0.8 mg), and vitamin B12 (0.5 mg) for 6 months also improved psychological well-being in people with long-standing celiac disease who had poor psychological well-being despite being on a strict gluten-free diet.68
2 Stars
Depression and Premenstrual Syndrome
Take under medical supervision: 100 to 300 mg daily
Several studies indicate that supplementing with vitamin B6 helps alleviate depression, including depression associated with PMS.

Oral contraceptives can deplete the body of vitamin B6 , a nutrient needed for maintenance of normal mental functioning. Double-blind research shows that women who are depressed and who have become depleted of vitamin B6 while taking oral contraceptives typically respond to vitamin B6 supplementation.69 In one trial, 20 mg of vitamin B6 were taken twice per day. Some evidence suggests that people who are depressed—even when not taking the oral contraceptive—are still more likely to be B6 deficient than people who are not depressed.70

Several clinical trials also indicate that vitamin B6 supplementation helps alleviate depression associated with premenstrual syndrome (PMS),71 although the research remains inconsistent.72 Many doctors suggest that women who have depression associated with PMS take 100–300 mg of vitamin B6 per day—a level of intake that requires supervision by a doctor.

2 Stars
Intermittent Claudication (Alpha-Linolenic Acid, Fish Oil, Folic Acid, Oleic Acid, Vitamin E)
200 mg of EPA and 130 mg of DHA daily, plus small amounts of vitamin B6, folic acid, vitamin E, oleic acid, and alpha-linolenic acid
In one study, men with intermittent claudication who drank a milk product fortified with fish oil, vitamin B6, folic acid, vitamin E, oleic acid, and alpha-linolenic acid could walk further without pain than those who drank regular milk.

Men with intermittent claudication consumed a fortified milk product or regular milk daily for one year. The fortified product provided daily 130 mg of eicosapentaenoic acid and 200 mg of docosahexaenoic acid (EPA and DHA, two fatty acids in fish oil ), small amounts of supplemental vitamin E , folic acid , and vitamin B6 , and additional amounts of oleic acid and alpha-linolenic acid. Compared with regular milk, the fortified milk product significantly increased the distance the participants could walk before the onset of pain .73

2 Stars
Low Back Pain (Vitamin B1, Vitamin B12)
Take under medical supervision: 50 to 100 mg each of vitamins B1 and B6, and 250 to 500 mcg of vitamin B12, all taken three times per day
A combination of vitamin B1, vitamin B6, and vitamin B12 may prevent a common type of back pain linked to vertebral syndromes and may reduce the need for anti-inflammatory medications.

A combination of vitamin B1 , vitamin B6 , and vitamin B12 has proved useful for preventing a relapse of a common type of back pain linked to vertebral syndromes,74 as well as reducing the amount of anti-inflammatory medications needed to control back pain, according to double-blind trials.75 Typical amounts used have been 50–100 mg each of vitamins B1 and B6, and 250–500 mcg of vitamin B12, all taken three times per day.76 , 77 Such high amounts of vitamin B6 require supervision by a doctor.

2 Stars
Macular Degeneration (Folic Acid, Vitamin B12)
2.5 mg folic acid, 50 mg vitamin B6, and 1 mg vitamin B12
In a double-blind study of female health professionals who had cardiovascular disease or risk factors, daily supplementation with folic acid, vitamin B6, and vitamin B12 significantly decreased age-related macular degeneration.

In a double-blind study of female health professionals who had cardiovascular disease or cardiovascular disease risk factors, daily supplementation with folic acid (2.5 mg), vitamin B6 (50 mg), and vitamin B12 (1 mg) for 7.3 years significantly decreased the incidence of age-related macular degeneration.78 

 

2 Stars
MSG Sensitivity
Refer to label instructions
In one study, eight out of nine people stopped reacting to MSG when given vitamin B6. Many doctors suggest that people having MSG-sensitivity symptoms try supplementing with vitamin B6 for three months as a trial.

Years ago, researchers discovered that animals who were deficient in vitamin B6 could not properly process MSG.79 Typical reactions to MSG have also been linked to vitamin B6 deficiency in people.80 In one study, eight out of nine such people stopped reacting to MSG when given 50 mg of vitamin B6 per day for at least 12 weeks.

The actual percentage of people with MSG sensitivity who are deficient in vitamin B6 and who respond to B6 supplementation is unknown. Nonetheless, many doctors suggest that people having MSG-sensitivity symptoms try supplementing with vitamin B6 for three months as a trial.

2 Stars
Pregnancy and Postpartum Support and High Homocysteine
750 mg daily taken under the supervision of a doctor
Women who habitually miscarry have been found to have high homocysteine levels. Vitamin B6 may reduce these levels and increase the chances of a successful pregnancy.
The relationship between folate status and the risk of miscarriage is also somewhat unclear. In some studies, women who have had habitual miscarriages were found to have elevated levels of homocysteine (a marker of folate deficiency).81 , 82 , 83 , 84 In a preliminary study, 22 women with recurrent miscarriages who had elevated levels of homocysteine were treated with 15 mg per day of folic acid and 750 mg per day of vitamin B6 , prior to and throughout their next pregnancy. This treatment reduced homocysteine levels to normal and was associated with 20 successful pregnancies.85 It is not known whether supplementing with these vitamins would help prevent miscarriages in women with normal homocysteine levels. As the amounts of folic acid and vitamin B6 used in this study were extremely large and potentially toxic, this treatment should be used only with the supervision of a doctor.
2 Stars
Schizophrenia
Consult a qualified healthcare practitioner
Vitamin B6 has been used in combination with niacin in the treatment of schizophrenia with some reported benefits.

The term “orthomolecular psychiatry” was coined by Linus Pauling in 1968 to refer to the treatment of psychiatric illnesses with substances (such as vitamins) that are normally present in the body. In orthomolecular psychiatry, high amounts of vitamins are sometimes used, not to correct a deficiency per se, but to create a more optimal biochemical environment. The mainstay of the orthomolecular approach to schizophrenia is niacin or niacinamide ( vitamin B3 ) in high amounts. In early double-blind trials, 3 grams of niacin daily resulted in a doubling of the recovery rate, a 50% reduction in hospitalization rates, and a dramatic reduction in suicide rates.86 In a preliminary trial, some schizophrenic patients continued a course of vitamins (4 to 10 grams of niacin or niacinamide, 4 grams of vitamin C , and 50 mg or more of vitamin B6 ) after being discharged from the hospital, while another group of patients discontinued the vitamins upon discharge. Both groups continued to take their psychiatric medications. Those who continued to take the vitamins had a 50% lower re-admission rate compared with those who did not.87 Several later double-blind trials, including trials undertaken by the Canadian Mental Health Association, have been unable to reproduce these positive results.88 , 89 Early supporters of niacin therapy contend that many of these trials were poorly designed.90 One clinical trial reported no greater improvement in a group of schizophrenic patients given 6 grams of niacin than in others given 3 mg of niacin; all patients were also being treated with psychiatric medications.91

There are potential side-effects of niacin therapy, including an uncomfortable flushing sensation, dermatitis (skin inflammation), heartburn , aggravation of peptic ulcers , increased blood sugar, increased panic and anxiety , and elevation of liver enzymes , which may indicate damage to liver cells. A positive side effect of niacin therapy is reduction of cholesterol levels . Some of these effects, such as flushing, gastric upset, and reduction of serum cholesterol, do not occur with the use of niacinamide .92 Because of the seriousness of some of these side effects, high amounts of niacin should not be used without the supervision of a healthcare practitioner.

Vitamin B6 has been used in combination with niacin in the orthomolecular approach to schizophrenia. Pioneers of orthomolecular medicine reported benefits from this combination. However, although two placebo-controlled trials found significant improvement when schizophrenic patients were given either 3 grams of niacin or 75 mg of pyridoxine along with their psychiatric medications, this improvement was lost when the two vitamins were combined.93 , 94 In a double-blind trial, schizophrenic patients were given either a vitamin program based on their individual laboratory tests or a placebo (25 mg of vitamin C ) in addition to their psychiatric medications. The vitamin program included large amounts of various B vitamins, as well as vitamin C and vitamin E . After five months, the number of patients who improved was not different in the vitamin group compared with the placebo group.95

Clinical trials of the effects of vitamin B6 have yielded differing results. The results of supplementation with 100 mg daily in one schizophrenic patient included dramatic reduction in side effects from medication, as well as reduction in schizophrenic symptoms.96 In a preliminary trial, 60 mg per day of vitamin B6 resulted in symptomatic improvement in only 5% of schizophrenic patients after four weeks.97 Another preliminary trial, however, found that a higher amount of vitamin B6—50 mg three times daily given for eight to twelve weeks—in addition to psychiatric medications, did bring about significant improvements in schizophrenic patients. These patients experienced a better sense of well-being, increased motivation, and greater interest in their “personal habits and their environment.”98

L-tryptophan is the amino acid precursor of serotonin, a neurotransmitter (chemical messenger in the brain). There is evidence that L-tryptophan levels in schizophrenic people are lower than in non-schizophrenics99 and the way the body uses L-tryptophan is altered in people with schizophrenia.100 , 101 In a preliminary trial, patients with schizophrenia were given 2–8 grams of L-tryptophan and 100 mg of vitamin B6 daily. This resulted in decreased agitation and less fear and anxiety , but these improvements were not as great as those achieved with psychiatric medications.102 It is not clear whether the benefits seen in this trial were due to vitamin B6, L-tryptophan, or a combination of the two. No other clinical trials using L-tryptophan have been published. L-tryptophan is currently available by prescription only.

2 Stars
Schizophrenia and High Homocysteine (Folic Acid, Vitamin B12)
Take folic acid (2 mg), vitamin B6 (25 mg), and vitamin B12 (400 mcg) daily
People with schizophrenia who have high homocysteine levels may improve symptoms by supplementing with folic acid, vitamin B6, and vitamin B12.
In another double-blind study, daily supplementation with folic acid (2 mg), vitamin B6 (25 mg), and vitamin B12 (400 mcg) for three months improved symptoms of schizophrenia compared with a placebo.103 All of the participants in this study had elevated blood levels of homocysteine, which can be decreased by taking these three B vitamins. Based on this study, it would seem reasonable to measure homocysteine levels in people with schizophrenia and, if they are elevated, to supplement with folic acid, vitamin B6, and vitamin B12.
2 Stars
Tooth Decay
For adults: 20 mg per day in capsules or lozenges; for children: 9 mg daily
Vitamin B6 appears to increase growth of beneficial mouth bacteria and decrease growth of cavity-causing bacteria.

Test tube studies show that vitamin B6 increases growth of beneficial mouth bacteria and decreases growth of cavity-causing bacteria.104 A double-blind study found that pregnant women who supplemented with 20 mg per day of vitamin B6 had significantly fewer new caries and fillings during pregnancy.105 Lozenges containing vitamin B6 were more effective than capsules in this study, suggesting an important topical effect. Another double-blind study gave children oral lozenges containing 3 mg of vitamin B6 three times per day for eight months, but reported only insignificant reductions in new cavities.106

2 Stars
Type 1 Diabetes
1,800 mg daily of of pyridoxine alpha-ketoglutarate or 50 mg daily pyridoxine
People with diabetes often have low vitamin B6 levels. Supplementing with the vitamin may restore levels and improve glucose tolerance.

Blood levels of vitamin B1 (thiamine) have been found to be low in people with type 1 diabetes.107 A controlled trial in Africa found that supplementing with both vitamin B1 (25 mg per day) and vitamin B6 (50 mg per day) led to significant improvement of symptoms of diabetic nerve damage (neuropathy) after four weeks.108 However, since this was a trial conducted among people in a vitamin B1–deficient developing country, these improvements might not occur in other people with diabetes. Another trial found that combining vitamin B1 (in a special fat-soluble form) and vitamin B6 plus vitamin B12 in high but variable amounts led to improvement in some aspects of diabetic neuropathy in 12 weeks.109 As a result, some doctors recommend that people with diabetic neuropathy supplement with vitamin B1, though the optimal level of intake remains unknown.

110

Many people with diabetes have low blood levels of vitamin B6 .111 , 112 Levels are even lower in people with diabetes who also have neuropathy.113 In a trial that included people with type 1 diabetes, 1,800 mg per day of a special form of vitamin B6—pyridoxine alpha-ketoglutarate—improved glucose tolerance dramatically.114 Vitamin B6 may also reduce the amount of glycosylation, so taking adequate amounts of this vitamin may be beneficial for all people with diabetes.115
2 Stars
Type 2 Diabetes
1,800 mg pyridoxine alpha-ketoglutarate daily or 50 mg daily pyridoxine daily
People with diabetes often have low vitamin B6 levels. Supplementing with the vitamin may restore levels and improve glucose tolerance.

Many people with diabetes have low blood levels of vitamin B6 .116 , 117 Levels are even lower in people with diabetes who also have nerve damage (neuropathy).118 Vitamin B6 supplementation has improved glucose tolerance in women with diabetes caused by pregnancy.119 , 120 Vitamin B6 supplementation is also effective for glucose intolerance induced by birth control pills.121 In a trial that included people with type 2 diabetes, 1,800 mg per day of a special form of vitamin B6—pyridoxine alpha-ketoglutarate—improved glucose tolerance dramatically.122 Standard vitamin B6 has helped in some,123 but not all, trials.124

2 Stars
Type 2 Diabetes and Diabetic Neuropathy (Vitamin B1)
25 mg daily, with 50 mg of vitamin B6 daily
Taking vitamin B1 combined with vitamin B6 may improve symptoms of diabetic neuropathy.

A controlled trial in Africa found that supplementing with both vitamin B1 (25 mg per day) and vitamin B6 (50 mg per day) led to significant improvement of symptoms of diabetic neuropathy after four weeks.125 However, since this was a trial conducted among people in a vitamin B1–deficient developing country, these improvements might not occur in other people with diabetes. Another trial found that combining vitamin B1 (in a special fat-soluble form) and vitamin B6 plus vitamin B12 in high but variable amounts led to improvement in some aspects of diabetic neuropathy in 12 weeks.126 As a result, some doctors recommend that people with diabetic neuropathy supplement with vitamin B1, though the optimal level of intake remains unknown.

2 Stars
Vertigo
Consult a qualified healthcare practitioner
Studies have shown vitamin B6 to be effective at reducing symptoms.

Two preliminary human studies reported that vitamin B6 supplementation reduced symptoms of vertigo produced with drugs in a laboratory setting.127 Vitamin B6 supplementation has not been studied in BPPV or other forms of vertigo and may not share the same causative mechanism as experimentally induced vertigo.

1 Star
Acne Vulgaris
Refer to label instructions
While not proven in research, some reports suggest that it may alleviate adolescent and premenstrual acne, however, another report has suggested that it might make acne worse.

A preliminary report suggested that vitamin B6 at 50 mg per day may alleviate premenstrual flare-ups of acne experienced by some women.128 While no controlled research has evaluated this possibility, an older controlled trial of resistant adolescent acne found that 50–250 mg per day decreased skin oiliness and improved acne in 75% of the participants.129 However, another preliminary report suggested that vitamin B6 supplements might exacerbate acne vulgaris.130

1 Star
Alcohol Withdrawal
Refer to label instructions
Alcohol-related anxiety may be improved by a combination of vitamin B6, vitamin C, niacin, and vitamin E, though the high amounts of niacin and vitamin B6 used in the study need a doctor’s supervision.

The daily combination of 3 grams of vitamin C , 3 grams of niacin , 600 mg of vitamin B6 , and 600 IU of vitamin E has been used by researchers from the University of Mississippi Medical Center in an attempt to reduce anxiety and depression in alcoholics.131 Although the effect of vitamin supplementation was no better than placebo in treating alcohol-associated depression, the vitamins did result in a significant drop in anxiety within three weeks of use. Because of possible side effects, anyone taking such high amounts of niacin and vitamin B6 must do so only under the care of a doctor.

1 Star
Alzheimer’s Disease (Coenzyme Q10, Iron)
Refer to label instructions
A combination of coenzyme Q10, iron (sodium ferrous citrate), and vitamin B6 may improve mental status in people with Alzheimer’s disease.

In a preliminary report, two people with a hereditary form of Alzheimer’s disease received daily: coenzyme Q10 (60 mg), iron (150 mg of sodium ferrous citrate), and vitamin B6 (180 mg). Mental status improved in both patients, and one became almost normal after six months.132

1 Star
Amenorrhea
Refer to label instructions
Preliminary evidence found that vitamin B6 restored menstruation and normalized hormone levels in three women with amenorrhea who had high prolactin levels.

Prolactin is a hormone that may be elevated in some cases of amenorrhea. A preliminary trial of 200 to 600 mg daily of vitamin B6 restored menstruation and normalized prolactin levels in three amenorrheic women with high initial prolactin levels; however, 600 mg daily of vitamin B6 had no effect on amenorrheic women who did not have high prolactin levels.133 A number of other small, preliminary trials have not demonstrated an effect of either oral or injected vitamin B6 on prolactin levels,134 , 135 , 136 , 137 , 138 and they also have reported inconsistent effects on restoring menstruation.139 , 140 , 141 Larger, controlled trials are needed to better determine the usefulness of vitamin B6 in amenorrhea.

1 Star
Atherosclerosis
Refer to label instructions
Blood levels of the amino acid homocysteine have been linked to atherosclerosis and heart disease in most research. Taking vitamin B6 may help lower homocysteine levels.

Blood levels of an amino acid called homocysteine have been linked to atherosclerosis and heart disease in most research,142 , 143 though uncertainty remains about whether elevated homocysteine actually causes heart disease.144 , 145 Although some reports have found associations between homocysteine levels and dietary factors, such as coffee and protein intakes,146 evidence linking specific foods to homocysteine remains preliminary. Higher blood levels of vitamin B6 , vitamin B12 , and folic acid are associated with low levels of homocysteine147 and supplementing with these vitamins lowers homocysteine levels.148 , 149

While several trials have consistently shown that B6, B12, and folic acid lower homocysteine, the amounts used vary from study to study. Many doctors recommend 50 mg of vitamin B6, 100–300 mcg of vitamin B12, and 500–800 mcg of folic acid. Even researchers finding only inconsistent links between homocysteine and heart disease have acknowledged that a B vitamin might offer protection against heart disease independent of the homocysteine-lowering effect.150 In one trial, people with normal homocysteine levels had demonstrable reversal of atherosclerosis when supplementing B vitamins (2.5 mg folic acid, 25 mg vitamin B6, and 250 mcg of vitamin B12 per day).151 Similar results were seen in another study.152

For the few cases in which vitamin B6, vitamin B12, and folic acid fail to normalize homocysteine, adding 6 grams per day of betaine (trimethylglycine) may be effective.153 Of these four supplements, folic acid appears to be the most important.154 Attempts to lower homocysteine by simply changing the diet rather than by using vitamin supplements have not been successful.155

1 Star
Attention Deficit–Hyperactivity Disorder
Refer to label instructions
In one study, high amounts of vitamin B6 was more effective than methylphenidate (Ritalin). A healthcare practitioner knowledgeable in nutrition must be consulted when using high amounts of this vitamin.

B vitamins , particularly vitamin B6 , have also been used for ADHD. Deficient levels of vitamin B6 have been detected in some ADHD patients.156 In a study of six children with low blood levels of the neurotransmitter (chemical messenger) serotonin, vitamin B6 supplementation (15–30 mg per 2.2 pounds of body weight per day) was found to be more effective than methylphenidate (Ritalin®). However, lower amounts of vitamin B6 were not beneficial.157 The effective amount of vitamin B6 in this study was extremely large and could potentially cause nerve damage, although none occurred in this study. A practitioner knowledgeable in nutrition must be consulted when using high amounts of vitamin B6. High amounts of other B vitamins have shown mixed results in relieving ADHD symptoms.158 , 159

1 Star
Bulimia (L-Tryptophan)
Refer to label instructions
Vitamin B6, when taken with L-tryptophan, has been shown to improve eating behavior, feelings about eating, and mood among women with bulimia.

People with eating disorders who restrict their food intake are at risk for multiple nutrient deficiencies, including protein, calcium , iron , riboflavin , niacin ,160 folic acid ,161 vitamin A , vitamin C ,162 and vitamin B6 ,163 and essential fatty acids.164 A general multivitamin-mineral formula can reduce the detrimental health effects of these deficiencies.

Serotonin, a hormone that helps regulate food intake and appetite, is synthesized in the brain from the amino acid L-tryptophan. Preliminary data suggest that some people with bulimia have low serotonin levels.165 Researchers have reported that bulimic women with experimentally induced tryptophan deficiency tend to eat more and become more irritable compared to healthy women fed the same diet,166 , 167 though not all studies have demonstrated these effects.168

Weight-loss diets result in lower L-tryptophan and serotonin levels in women,169 which could theoretically trigger bingeing and purging in susceptible people. However, the benefits of L-tryptophan supplementation are unclear. One small, double-blind trial reported significant improvement in eating behavior, feelings about eating, and mood among women with bulimia who were given 1 gram of L-tryptophan and 45 mg of vitamin B6 three times per day.170 Other double-blind studies using only L-tryptophan have failed to confirm these findings.171 , 172 L-tryptophan is available by prescription only; most drug stores do not carry it, but “compounding” pharmacies do. Most cities have at least one compounding pharmacy, which prepares customized prescription medications to meet individual patient’s needs.

1 Star
Celiac Disease
Refer to label instructions
For people with celiac disease who experience depression even after following a gluten-free diet, supplementing with vitamin B6 may be beneficial.
In one trial, 11 people with celiac disease suffered from persistent depression despite being on a gluten-free diet for more than two years. However, after supplementation with vitamin B6 (80 mg per day) for six months, the depression disappeared.173
1 Star
Epilepsy
Refer to label instructions
Vitamin B6 has helped children with seizures related to a genetic enzyme defect. However, it is not known whether supplementation would benefit people with epilepsy.

Vitamin B6 has been used to treat infants and small children who have seizures related to a genetic enzyme defect.174 , 175 , 176 , 177 However, this condition is not considered true epilepsy, and whether people with epilepsy would benefit from taking vitamin B6 supplements is unknown.

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Fibrocystic Breast Disease
Refer to label instructions
Some studies have found that supplementing with vitamin B6 reduces FBD symptoms.

The effectiveness of vitamin B6 remains uncertain. Some,178 but not all,179 studies find that B6 supplementation reduces symptoms. Since vitamin B6 supplementation is effective for relieving the symptoms of premenstrual syndrome (PMS), in addition to breast tenderness, women should discuss the use of vitamin B6 with their healthcare provider.

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Heart Attack
Refer to label instructions
Taking vitamin B6 may reduce blood levels of homocysteine. High homocysteine levels have been linked to an increased heart attack risk.

High blood levels of the amino acid homocysteine have been linked to an increased risk of heart attack in most,180 , 181 , 182 , 183 though not all,184 , 185 studies. A blood test screening for levels of homocysteine, followed by supplementation with 400 mcg of folic acid and 500 mcg of vitamin B12 per day could prevent a significant number of heart attacks, according to one analysis.186 Folic acid 187 , 188 and vitamins B6 and B12 are known to lower homocysteine.189

There is a clear association between low blood levels of folate and increased risk of heart attacks in men.190 Based on the available research, some doctors recommend 50 mg of vitamin B6, 100–300 mcg of vitamin B12, and 500–800 mcg of folic acid per day for people at high risk of heart attack.

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HIV and AIDS Support
Refer to label instructions
Vitamin B6 deficiency was found in more than one-third of HIV-positive men, deficiency was associated with decreased immune function in this group. Supplementing with the vitamin may improve survival rate.

In HIV-positive people with B-vitamin deficiency, the use of B-complex vitamin supplements appears to delay progression to and death from AIDS.191 Thiamine ( vitamin B1 ) deficiency has been identified in nearly one-quarter of people with AIDS.192 It has been suggested that a thiamine deficiency may contribute to some of the neurological abnormalities that are associated with AIDS. Vitamin B6 deficiency was found in more than one-third of HIV-positive men; vitamin B6 deficiency was associated with decreased immune function in this group.193 In a population study of HIV-positive people, intake of vitamin B6 at more than twice the recommended dietary allowance (RDA is 2 mg per day for men and 1.6 mg per day for women) was associated with improved survival.194 Low blood levels of folic acid and vitamin B12 are also common in HIV-positive people.195

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Hypoglycemia
Refer to label instructions
Vitamin B6 helps control blood sugar levels in diabetics, and since there are similarities in the way the body regulates high and low blood sugar levels, it might be helpful for hypoglycemia as well.

Research has shown that supplementing with chromium (200 mcg per day)196 or magnesium (340 mg per day)197 can prevent blood sugar levels from falling excessively in people with hypoglycemia. Niacinamide (vitamin B3) has also been found to be helpful for hypoglycemic people.198 Other nutrients, including vitamin C , vitamin E , zinc , copper , manganese , and vitamin B6 , may help control blood sugar levels in diabetics .199 Since there are similarities in the way the body regulates high and low blood sugar levels, these nutrients might be helpful for hypoglycemia as well, although the amounts needed for that purpose are not known.

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Kidney Stones
Refer to label instructions
Taking vitamin B6 with magnesium can inhibit oxalate stone formation.

Both magnesium and vitamin B6 are used by the body to convert oxalate into other substances. Vitamin B6 deficiency leads to an increase in kidney stones as a result of elevated urinary oxalate.200 Vitamin B6 is also known to reduce elevated urinary oxalate in some stone formers who are not necessarily B6 deficient.201 , 202

Years ago, the Merck Manual recommended 100–200 mg of vitamin B6 and 200 mg of magnesium per day for some kidney stone formers with elevated urinary oxalate.203 Most trials have shown that supplementing with magnesium204 , 205 , 206 and/or vitamin B6207 , 208 significantly lowers the risk of forming kidney stones. Results have varied from only a slight reduction in recurrences209 to a greater than 90% decrease in recurrences.210

Optimal supplemental levels of vitamin B6 and magnesium for people with kidney stones remain unknown. Some doctors advise 200–400 mg per day of magnesium. While the effective intake of vitamin B6 appears to be as low as 10–50 mg per day, certain people with elevated urinary oxalate may require much higher amounts, and therefore require medical supervision. In some cases, as much as 1,000 mg of vitamin B6 per day (a potentially toxic level) has been used successfully.211

Doctors who do advocate use of magnesium for people with a history of stone formation generally suggest the use of magnesium citrate because citrate itself reduces kidney stone recurrences. As with calcium supplementation, it appears important to take magnesium with meals in order for it to reduce kidney stone risks by lowering urinary oxalate.212

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Osgood-Schlatter Disease (Manganese, Zinc)
Refer to label instructions
Some doctors have reported good results using a combination of zinc, manganese, and vitamin B6 for people with Osgood-Schlatter disease.

Another group of doctors has reported good results using a combination of zinc , manganese , and vitamin B6 for people with Osgood-Schlatter disease; however, the amounts of these supplements were not mentioned in the report.213 Most physicians would consider reasonable daily amounts of these nutrients for adolescents to be 15 mg of zinc, 5 to 10 mg of manganese, and 25 mg of vitamin B6. Larger amounts might be used with medical supervision.

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Osteoporosis and High Homocysteine
Refer to label instructions
Homocystinuria, a condition associated with high homocysteine levels, frequently causes osteoporosis. By lowering homocysteine levels, vitamin B6 may help prevent osteoporosis.
Folic acid , vitamin B6 , and vitamin B12 are known to reduce blood levels of the amino acid homocysteine, and homocystinuria, a condition associated with high homocysteine levels, frequently causes osteoporosis. Therefore, some researchers have suggested that these vitamins might help prevent osteoporosis by lowering homocysteine levels.214 In a double-blind study of people who had suffered a stroke and had high homocysteine levels, daily supplementation with 5 mg of folic acid and 1,500 mcg of vitamin B12 for two years reduced the incidence of fractures by 78%, compared with a placebo.215 The reduction in fracture risk appeared to be due to an improvement in bone quality, rather than to a change in bone mineral density. However, supplementation with these vitamins did not reduce fracture risk in people who had only mildly elevated homocysteine levels and relatively high pretreatment folic acid levels.216 For the purpose of lowering homocysteine, amounts of folic acid and vitamins B6 and B12 found in high-potency B-complex supplements and multivitamins should be adequate.
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Parkinson’s Disease
Refer to label instructions
Vitamin B6 has been reported to improve Parkinson’s symptoms. It can be used in conjunction with L-dopa plus carbidopa (Sinemet) or selegiline (Eldepryl, Atapryl), rather than with L-dopa alone.
Although vitamin B6 was reported many years ago in preliminary research to improve symptoms of Parkinson’s disease,217 it must not be used by people taking L-dopa alone. Taking vitamin B6 with L-dopa increase the conversion of L-dopa to dopamine outside the brain,218 , 219 thereby reducing delivery of dopamine to the brain., However, vitamin B6 can be used in conjunction with L-dopa plus carbidopa (Sinemet) or seglegiline (Eldepryl, Atapryl).220
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Photosensitivity
Refer to label instructions
Vitamin B6 has been used to successfully reduce reactions to sunlight.

Cases have been reported of people with photosensitivity who responded to vitamin B6 supplementation.221 , 222 Amounts of vitamin B6 used to successfully reduce reactions to sunlight have varied considerably. Some doctors suggest a trial of 100 to 200 mg per day for three months. People wishing to take more than 200 mg of vitamin B6 per day should do so only under medical supervision.

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Pre- and Post-Surgery Health
Refer to label instructions
In one trial, a combination of vitamins B1, B6, and B12 before and after surgery prevented post-surgical reductions in immune activity.

Vitamin B1 , given as intramuscular injections of 120 mg daily for several days before surgery, resulted in less reduction of immune system activity after surgery in a preliminary trial.223 In a controlled trial, an oral B vitamin combination providing 100 mg of B1, 200 mg of vitamin B6 , and 200 mcg of vitamin B12 daily given for five weeks before surgery and for two weeks following surgery also prevented post-surgical reductions in immune activity.224 However, no research has explored any other benefits of B vitamin supplementation in surgery patients.

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Preeclampsia
Refer to label instructions
Supplementing with vitamin B6 and folic acid may lower homocysteine levels. Elevated homocysteine damages the lining of blood vessels and can lead to the preeclamptic symptoms.

Women with preeclampsia have been shown to have elevated blood levels of homocysteine .225 , 226 , 227 , 228 Research indicates elevated homocysteine occurs prior to the onset of preeclampsia.229 Elevated homocysteine damages the lining of blood vessels,230 , 231 , 232 , 233 , 234 , 235 , 236 which can lead to the preeclamptic signs of elevated blood pressure , swelling, and protein in the urine.237

In one preliminary trial, women with a previous pregnancy complicated by preeclampsia and high homocysteine supplemented with 5 mg of folic acid and 250 mg of vitamin B6 per day, successfully lowering homocysteine levels.238 In another trial studying the effect of vitamin B6 on preeclampsia incidence, supplementation with 5 mg of vitamin B6 twice per day significantly reduced the incidence of preeclampsia. Women in that study were not, however, evaluated for homocysteine levels.239 In fact, no studies have yet determined whether lowering elevated homocysteine reduces the incidence or severity of preeclampsia. Nevertheless, despite a lack of proof that elevated homocysteine levels cause preeclampsia, many doctors believe that pregnant women with elevated homocysteine should attempt to reduce those levels to normal.

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Sickle Cell Anemia
Refer to label instructions
Vitamin B6 has been shown to have anti-sickling effects on the red blood cells. It can also correct vitamin B6 deficiency, which is common in people with sickle cell anemia.

Preliminary research has found that patients with sickle cell anemia are more likely to have elevated blood levels of homocysteine compared to healthy people.240 , 241 Elevated homocysteine is recognized as a risk factor for cardiovascular disease .242 In particular, high levels of homocysteine in sickle cell anemia patients have been associated with a higher incidence of stroke .243 Deficiencies of vitamin B6 , vitamin B12, and folic acid occur more frequently in people with sickle cell anemia than in others244 , 245 , 246 and are a cause of high homocysteine levels.247 A controlled trial found homocysteine levels were reduced 53% in children with sickle cell anemia receiving a 2–4 mg supplement of folic acid per day, depending on age, but vitamin B6 or B12 had no effect on homocysteine levels.248 A double-blind trial of children with sickle cell anemia found that children given 5 mg of folic acid per day had less painful swelling of the hands and feet compared with those receiving placebo, but blood abnormalities and impaired growth rate associated with sickle cell anemia were not improved.249 In the treatment of sickle cell anemia, folic acid is typically supplemented in amounts of 1,000 mcg daily.250 Anyone taking this amount of folic acid should have vitamin B12 status assessed by a healthcare professional.

In test tube studies, vitamin B6 has been shown to have anti-sickling effects on the red blood cells of people with sickle cell anemia.251 , 252 Vitamin B6 deficiency has been reported in some research to be more common in people with sickle cell anemia than in healthy people.253 , 254 In a controlled trial, five sickle cell anemia patients with evidence of vitamin B6 deficiency were given 50 mg of vitamin B6 twice daily. The deficiency was reversed with this supplement, but improvement in anemia was slight and considered insignificant.255 Therefore, evidence in support of vitamin B6 supplementation for people with sickle cell anemia remains weak.

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Stroke and High Homocysteine
Refer to label instructions
Elevated blood levels of homocysteine have been linked to stroke risk in most studies. Supplementing with vitamin B6 may lower homocysteine levels and reduce stroke risk.

Elevated blood levels of homocysteine , a toxic amino acid byproduct, have been linked to risk of stroke in most studies.256 , 257 , 258 Supplementation with folic acid , vitamin B6 , and vitamin B12 generally lowers homocysteine levels in humans.259 , 260 , 261 In a pooled analysis (meta-analysis) of eight randomized trials, folic acid supplementation in varying amounts (usually 0.5 mg to 5 mg per day) reduced stroke risk by 18%.262

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Tardive Dyskinesia
Refer to label instructions
In some studies, taking vitamin B6 along with other nutrients appeared to prevent the development of tardive dyskinesia.

During a ten-year period, doctors at the North Nassau Mental Health Center in New York treated approximately 11,000 people with schizophrenia with a megavitamin regimen that included vitamin C (up to 4 grams per day), vitamin B3 —either as niacin or niacinamide—(up to 4 grams per day), vitamin B6 (up to 800 mg per day), and vitamin E (up to 1,200 IU per day). During that time, not a single new case of TD was seen, even though many of the people were taking neuroleptic drugs.263 Another psychiatrist who routinely used niacinamide , vitamin C, and vitamin B-complex over a 28-year period rarely saw TD develop in her patients.264 Further research is needed to determine which nutrients or combinations of nutrients were most important for preventing TD. The amounts of niacinamide and vitamin B6 used in this research may cause significant side effects and may require monitoring by a doctor.

How It Works

How to Use It

The most common supplemental intake is 10–25 mg per day. However, high amounts (100–200 mg per day or even more) may be recommended for certain conditions.

Where to Find It

Potatoes, bananas, raisin bran cereal, lentils, liver, turkey, and tuna are all good sources of vitamin B6.

Possible Deficiencies

Vitamin B6 deficiencies are thought to be very rare. Vitamin B6 deficiency can cause impaired immunity , skin lesions, and mental confusion. A marginal deficiency sometimes occurs in alcoholics , patients with kidney failure, and women using oral contraceptives. Some doctors believe that most diets do not provide optimal amounts of this vitamin. People with kidney failure have an increased risk of vitamin B6 deficiency.265 Vitamin B6 has also been reported to be deficient in some people with chronic fatigue syndrome .266

Interactions

Interactions with Supplements, Foods, & Other Compounds

Since vitamin B6 increases the bioavailability of magnesium , these nutrients are sometimes taken together.

Interactions with Medicines

Certain medicines interact with this supplement.

Types of interactions: Beneficial Adverse Check

Replenish Depleted Nutrients

  • Carbamazepine

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.268 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. On the other hand, supplementation with large amounts of vitamin B6 (80–200 mg per day) has been reported to reduce blood levels of some anticonvulsant drugs, which could theoretically trigger seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

  • Cortisone

    Corticosteroids may increase the loss of vitamin B6.270 One double-blind study of people with asthma failed to show any added benefit from taking 300 mg per day of vitamin B6 along with inhaled steroids.271 Therefore, while small amounts of vitamin B6 may be needed to prevent deficiency, large amounts may not provide added benefit. Some doctors recommend that people taking corticosteroids for longer than two weeks supplement with at least 2 mg of vitamin B6 per day.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Cycloserine

    Cycloserine may interfere with calcium and magnesium absorption.272 The clinical significance of these interactions is unclear.

    Cycloserine may interfere with the absorption and/or activity of folic acid, vitamin B6, and vitamin B12.273 , 274 The clinical importance of this interaction is unclear.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Desogestrel-Ethinyl Estradiol

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.280 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

  • Dexamethasone

    Corticosteroids may increase the loss of vitamin B6.281 One double-blind study of people with asthma failed to show any added benefit from taking 300 mg per day of vitamin B6 along with inhaled steroids.282 Therefore, while small amounts of vitamin B6 may be needed to prevent deficiency, large amounts may not provide added benefit. Some doctors recommend that people taking corticosteroids for longer than two weeks supplement with at least 2 mg of vitamin B6 per day.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Erythromycin

    Erythromycin may interfere with the absorption and/or activity of calcium , folic acid , magnesium , vitamin B6 and vitamin B12 ,285 which may cause problems, especially with long-term erythromycin treatment. Until more is known, it makes sense for people taking erythromycin for longer than two weeks to supplement with a daily multivitamin-multimineral .

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Ethinyl Estradiol and Levonorgestrel
    Laboratory evidence of vitamin B6 deficiency is common in women taking oral contraceptives.289 In a double-blind trial, supplementation with 20 mg of vitamin B6 twice a day for 2 months improved depression in women taking oral contraceptives who had laboratory evidence of vitamin B6 deficiency.290 However, vitamin B6 did not relieve depression in women who did not have vitamin B6 deficiency.291
    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Ethinyl Estradiol and Norethindrone

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.292 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Ethinyl Estradiol and Norgestimate

    A review of literature suggests that women who use OCs may experience decreased vitamin B1 , B2 , B3 , B12 , C , and zinc levels.300 , 301 , 302 OC use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A .303 , 304 , 305 OCs may interfere with manganese absorption.306 The clinical importance of these actions remains unclear.

  • Ethinyl Estradiol and Norgestrel

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.308 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

  • Felbamate

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.310 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. On the other hand, supplementation with large amounts of vitamin B6 (80–200 mg per day) has been reported to reduce blood levels of some anticonvulsant drugs, which could theoretically trigger seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

  • Gabapentin

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.315 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. On the other hand, supplementation with large amounts of vitamin B6 (80–200 mg per day) has been reported to reduce blood levels of some anticonvulsant drugs, which could theoretically trigger seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Hydralazine

    Vitamin B6 can bind to hydralazine to form a complex that is excreted in the urine, increasing vitamin B6 loss.316 This may lead to vitamin B6 deficiency.317 People taking hydralazine should consult with their doctor to discuss the possibility of vitamin B6 supplementation.

  • Levetiracetam

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.320 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. On the other hand, supplementation with large amounts of vitamin B6 (80–200 mg per day) has been reported to reduce blood levels of some anticonvulsant drugs, which could theoretically trigger seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

  • Levonorgestrel

    A review of literature suggests that women who use OCs may experience decreased vitamin B1 , B2 , B3 , B12 , C , and zinc levels.322 , 323 , 324 OC use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A .325 , 326 , 327 OCs may interfere with manganese absorption.328 The clinical importance of these actions remains unclear.

  • Levonorgestrel-Ethinyl Estrad

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.330 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

  • Mestranol and Norethindrone

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.331 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

  • Methylprednisolone

    Corticosteroids may increase the loss of vitamin B6.332 One double-blind study of people with asthma failed to show any added benefit from taking 300 mg per day of vitamin B6 along with inhaled steroids.333 Therefore, while small amounts of vitamin B6 may be needed to prevent deficiency, large amounts may not provide added benefit. Some doctors recommend that people taking corticosteroids for longer than two weeks supplement with at least 2 mg of vitamin B6 per day.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Neomycin

    Neomycin can decrease absorption or increase elimination of many nutrients, including calcium , carbohydrates, beta-carotene , fats, folic acid , iron , magnesium , potassium , sodium, and vitamin A , vitamin B12 , vitamin D , and vitamin K .334 , 335 Surgery preparation with oral neomycin is unlikely to lead to deficiencies. It makes sense for people taking neomycin for more than a few days to also take a multivitamin-mineral supplement.

  • Norgestimate-Ethinyl Estradiol

    A review of literature suggests that women who use OCs may experience decreased vitamin B1 , B2 , B3 , B12 , C , and zinc levels.337 , 338 , 339 OC use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A .340 , 341 , 342 OCs may interfere with manganese absorption.343 The clinical importance of these actions remains unclear.

  • Oxcarbazepine

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.345 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. On the other hand, supplementation with large amounts of vitamin B6 (80–200 mg per day) has been reported to reduce blood levels of some anticonvulsant drugs, which could theoretically trigger seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Penicillamine

    Penicillamine may increase vitamin B6 excretion, reduce activity, and increase the risk for vitamin B6 deficiency.346 It makes sense for people taking penicillamine to supplement with small (5–20 mg per day) amounts of vitamin B6. Some researchers have suggested that as much as 50 mg per day of vitamin B6 may be necessary.347

  • Phenelzine

    Phenelzine has a chemical structure similar to other drugs ( isoniazid and hydralazine ) that can cause vitamin B6 deficiency. One case of phenelzine-induced vitamin B6 deficiency has been reported.348 Little is known about this interaction. People taking phenelzine should ask their doctor about monitoring vitamin B6 levels and considering supplementation.

  • Phenobarbital

    One controlled study revealed that supplementing with 200 mg of vitamin B6 daily for four weeks resulted in a 45% reduction in phenobarbital blood levels.349 Therefore, people taking phenobarbital should probably avoid supplementing with large amounts of vitamin B6.

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.350 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Phenytoin

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.351 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. On the other hand, supplementation with large amounts of vitamin B6 (80–200 mg per day) has been reported to reduce blood levels of some anticonvulsant drugs, which could theoretically trigger seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

  • Prednisolone

    Corticosteroids may increase the loss of vitamin B6.352 One double-blind study of people with asthma failed to show any added benefit from taking 300 mg per day of vitamin B6 along with inhaled steroids.353 Therefore, while small amounts of vitamin B6 may be needed to prevent deficiency, large amounts may not provide added benefit. Some doctors recommend that people taking corticosteroids for longer than two weeks supplement with at least 2 mg of vitamin B6 per day.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Prednisone

    Corticosteroids may increase the loss of vitamin B6.354 One double-blind study of people with asthma failed to show any added benefit from taking 300 mg per day of vitamin B6 along with inhaled steroids.355 Therefore, while small amounts of vitamin B6 may be needed to prevent deficiency, large amounts may not provide added benefit. Some doctors recommend that people taking corticosteroids for longer than two weeks supplement with at least 2 mg of vitamin B6 per day.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Primidone

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.356 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. On the other hand, supplementation with large amounts of vitamin B6 (80–200 mg per day) has been reported to reduce blood levels of some anticonvulsant drugs, which could theoretically trigger seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

  • Sulfamethoxazole

    Sulfonamides, including sulfamethoxazole, can interfere with the activity of folic acid, vitamin B6, and vitamin K.359 This is generally not a problem when taking sulfamethoxazole for two weeks or less. People taking sulfamethoxazole for longer than two weeks should ask their doctor about nutrient monitoring and supplementation.

    Note: Since sulfamethoxazole is often prescribed in combination with trimethoprim (for example, in Bactrim or Septra), it may be easy to associate this interaction with trimethoprim. However, this interaction is not known to occur with trimethoprim alone.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Tetracycline

    Tetracycline can interfere with the activity of folic acid , potassium , and vitamin B2 , vitamin B6 , vitamin B12 , vitamin C , and vitamin K .360 This is generally not a problem when taking tetracycline for two weeks or less. People taking tetracycline for longer than two weeks should ask their doctor about vitamin and mineral supplementation. Taking 500 mg vitamin C simultaneously with tetracycline was shown to increase blood levels of tetracycline in one study.361 The importance of this interaction is unknown.

  • Theophylline

    Theophyline has been associated with depressed serum vitamin B6 levels in children with asthma362 and adults with chronic obstructive pulmonary disease .363 In a short-term study of healthy adults, theophylline reduced serum vitamin B6 levels and supplementation with vitamin B6 (10 mg per day) normalized vitamin B6 levels.364 Some doctors believe that it makes sense for people taking this drug to accompany it with 10 mg of vitamin B6 per day.

  • Topiramate

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.365 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. On the other hand, supplementation with large amounts of vitamin B6 (80–200 mg per day) has been reported to reduce blood levels of some anticonvulsant drugs, which could theoretically trigger seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

  • Trimethoprim/ Sulfamethoxazole

    Sulfonamides, including sulfamethoxazole , can interfere with the activity of folic acid and vitamin B6.366 This is generally not a problem when taking sulfamethoxazole for two weeks or less. People taking sulfamethoxazole for longer than two weeks should ask their doctor about nutrient monitoring and supplementation.

    TMP/SMX has, on rare occasions, been associated with anemia due to folic acid deficiency.367 This effect may be due to trimethoprim.368 TMP/SMX should be used with caution in patients with folic acid deficiency, for which a blood test is available. Folic acid replacement does not interfere with the antibacterial activity of TMP/SMX.369 People with AIDS -related pneumonia given TMP/SMX had a worse survival rate when folinic acid, an activated form of folic acid, was added.370

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Valproate

    Preliminary research has linked anticonvulsant therapy with possible depletion of vitamin B6 in children.372 One preliminary study found that a combination of 10–50 mg per 2.2 pounds of body weight of vitamin B6 plus valproic acid was more effective than valproic acid or vitamin B6 alone at treating children with recurrent seizures.373 On the other hand, supplementation with large amounts of vitamin B6 (80–200 mg per day) has been reported to reduce blood levels of some anticonvulsant drugs, which could theoretically trigger seizures. People taking anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Zonisamide

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.374 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. On the other hand, supplementation with large amounts of vitamin B6 (80–200 mg per day) has been reported to reduce blood levels of some anticonvulsant drugs, which could theoretically trigger seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

Reduce Side Effects

  • Desogestrel-Ethinyl Estradiol

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.279 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

  • Docetaxel

    Docetaxel may cause a reddening, swelling, and pain in hands and feet. Two cases have been reported of people suffering these drug-induced symptoms and responding to 50 mg of vitamin B6 given three times per day.283 Symptoms began to resolve in 12 to 24 hours and continued to improve for several weeks.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Ethinyl Estradiol and Levonorgestrel
    Laboratory evidence of vitamin B6 deficiency is common in women taking oral contraceptives.286 In a double-blind trial, supplementation with 20 mg of vitamin B6 twice a day for 2 months improved depression in women taking oral contraceptives who had laboratory evidence of vitamin B6 deficiency.287 However, vitamin B6 did not relieve depression in women who did not have vitamin B6 deficiency.288
  • Ethinyl Estradiol and Norethindrone

    A review of literature suggests that women who use OCs may experience decreased vitamin B1 , B2 , B3 , B12 , C , and zinc levels.293 , 294 , 295 OC use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A .296 , 297 , 298 OCs may interfere with manganese absorption.299 The clinical importance of these actions remains unclear.

  • Ethinyl Estradiol and Norgestimate

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.307 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

  • Ethinyl Estradiol and Norgestrel

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.309 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

  • Fenofibrate

    Increased blood levels of homocysteine are associated with increased risk of atherosclerosis and heart disease . One study revealed that fenofibrate dramatically increases blood homocysteine levels, though blood levels of vitamins were not reduced.311 In one study, supplementation with 10 mg per day of folic acid prevented the increase in homocysteine levels resulting from fenofibrate therapy.312 Further research is needed to determine whether supplemental  vitamin B6 and vitamin B12, which are also capable of lowering homocysteine levels, might lower fenofibrate-induced elevations in homocysteine levels.

  • Fluorouracil

    Fluorouracil occasionally causes problems on the skin of the palms and soles. Preliminary reports have appeared showing that 100 mg per day of vitamin B6 can sometimes eliminate the pain associated with this drug-induced condition.313 , 314

  • Levonorgestrel

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.321 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

  • Levonorgestrel-Ethinyl Estrad

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.329 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

  • Norgestimate-Ethinyl Estradiol

    Oral contraceptives have been associated with vitamin B6 depletion and clinical depression . In a small, double-blind study of women with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.336 Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.

  • Risperidone

    Vitamin E along with vitamin B6 was used to treat a side effect of risperidone called neuroleptic malignant syndrome in a 74-year-old woman, and results were encouraging.358 However, whether vitamin E and vitamin B6 supplementation might help prevent this condition in people taking risperidone is unknown.

Support Medicine

  • Amitriptyline

    Giving 10 mg per day each of vitamins B1 , B2 , and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did.267 The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Clomipramine

    Giving 10 mg per day each of vitamins B1 , B2 , and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did.269 The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Desipramine

    Giving 10 mg per day each of vitamins B1 , B2 , and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did.275 The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

    Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder .276 These levels did not improve the effects of imipramine in people with depression . Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

    The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.277 , 278

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Doxepin

    Giving 10 mg per day each of vitamins B1 , B2 , and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did.284 The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Hydroxychloroquine

    An individual who took hydroxychloroquine and vitamin B6 together for nine years experienced a complete disappearance of skin nodules caused by rheumatoid arthritis .318 Controlled study is needed to determine whether taking vitamin B6 with or without hydroxychloroquine might help eliminate nodules in people with rheumatoid arthritis.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Imipramine

    Giving 10 mg per day each of vitamins B1 , B2 , and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did.319 The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Nortriptyline

    Giving 10 mg per day each of vitamins B1 , B2 , and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did.344 The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Protriptyline

    Giving 10 mg per day each of vitamins B1 , B2 , and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did.357 The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Trimipramine

    Giving 10 mg per day each of vitamins B1 , B2 , and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did.371 The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.

Reduces Effectiveness

  • Phenobarbital

    One controlled study revealed that supplementing with 200 mg of vitamin B6 daily for four weeks resulted in a 45% reduction in phenobarbital blood levels.375 Therefore, people taking phenobarbital should probably avoid supplementing with large amounts of vitamin B6.

    One controlled study revealed that taking anticonvulsant drugs dramatically reduces blood levels of vitamin B6.376 A nutritional deficiency of vitamin B6 can lead to an increase in homocysteine blood levels, which has been associated with atherosclerosis . Vitamin B6 deficiency is also associated with symptoms such as dizziness, fatigue, mental depression , and seizures. People taking multiple anticonvulsant drugs should discuss with their doctor whether supplementing with vitamin B6 is advisable.

Potential Negative Interaction

  • none

Explanation Required

  • Carbidopa

    Test tube,377 animal,378 and preliminary human studies379 suggest that carbidopa may cause depletion of vitamin B6. However, the use of carbidopa with levodopa reduces the vitamin B6-depleting effects of levodopa.380 More research is needed to determine whether vitamin B6 supplementation is advisable when taking carbidopa.

  • Carbidopa-Levodopa

    Vitamin B6 supplementation above 5–10 mg per day reduces the effectiveness of levodopa.381 However, combining levodopa with carbidopa prevents this adverse effect, so vitamin B6 supplements may safely be taken with Sinemet® (carbidopa/levodopa).

  • Folic Acid

    Folic acid and vitamin B6 have been used to reduce elevated blood levels of homocysteine , which has been associated with atherosclerosis . One controlled study showed that taking 0.3 mg of folic acid together with 120 mg of vitamin B6 reduced homocysteine levels more than taking either vitamin alone. The study also revealed that long-term supplementation with vitamin B6 alone might reduce blood folic acid levels.382 Therefore, people with elevated blood homocysteine levels should supplement with both folic acid and vitamin B6.

  • Gentamicin

    Gentamicin administration has been associated with vitamin B6 depletion in rabbits.383 The authors of this study mention early evidence that vitamin B6 administration may protect against gentamicin-induced kidney damage.

  • Isoniazid

    Isoniazid can interfere with the activity of vitamin B6.384 Vitamin B6 supplementation is recommended, especially in people with poor nutritional status, to prevent development of isoniazid-induced peripheral neuritis (inflamed nerves).385 One case is reported in which injectable vitamin B6 reversed isoniazid-induced coma.386 In another case, however, 10 mg per day of vitamin B6 failed to reverse isoniazid-induced psychosis. The author suggested that higher amounts (e.g., 50 mg per day) may be needed.387 Although the optimal amount remains unknown, some doctors suggest that adults taking isoniazid supplement with 100 mg of vitamin B6 per day to prevent side effects. However, as animal studies suggest that very large amounts of vitamin B6 can interfere with the effect of isoniazid,388people taking isoniazid should consult their doctor to determine the appropriate amount of vitamin B6 to take.

The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

Side Effects

Side Effects

Vitamin B6 is usually safe, at intakes up to 200 mg per day in adults.389 However, neurological side effects can sometimes occur at that level.390 Levels higher than 200 mg are more likely to cause such problems. Vitamin B6 toxicity can damage sensory nerves, leading to numbness in the hands and feet as well as difficulty walking. The National Academy of Sciences performed an analysis of vitamin B6 studies. They determined the safe upper limit for long-term use is 100 mg per day. However, under supervision of a healthcare professional, up to 200 mg per day of vitamin B6 can be safely taken by most men and nonpregnant women for limited periods of time. Pregnant and breast-feeding women should not take more than 100 mg of vitamin B6 per day without a doctor’s supervision.

In a double-blind trial, people with diabetes who also had with kidney disease received a daily placebo or 2.5 mg of folic acid, 1 mg of vitamin B12, and 25 mg of vitamin B6 for three years. Compared with the placebo, vitamin supplementation accelerated the decline in kidney function and increased the incidence of cardiovascular events (such as heart attacks) and heart disease-related deaths.391 Based on this study, diabetics with kidney disease should not take these vitamins without a doctor's supervision.

References

1. Little DR. Ambulatory management of common forms of anemia. Am Fam Physician 1999;59:1598–604 [review].

2. Hodges RE, Sauberlich HE, Canham JE, et al. Hematopoietic studies in vitamin A deficiency. Am J Clin Nutr 1978;31:876–85 [review].

3. Bloem MW. Interdependence of vitamin A and iron: an important association for programmes of anaemia control. Proc Nutr Soc 1995;54:501–8 [review].

4. Lane M, Alfrey CP. The anemia of human riboflavin deficiency. Blood 1965;25:432–42.

5. Orehek AJ, Kollas CD. Refractory postpartum anemia due to vitamin B6 deficiency. Ann Intern Med 1997;126(10):834–5 [letter].

6. Iwama H, Iwase O, Hayashi S, et al. Macrocytic anemia with anisocytosis due to alcohol abuse and vitamin B6 deficiency. Rinsho Ketsueki 1998;39:1127–30 [in Japanese].

7. Hirschmann JV, Raugi GJ. Adult scurvy. J Am Acad Dermatol 1999;41:895–906 [review].

8. Summerfield AL, Steinberg FU, Gonzalez JG. Morphologic findings in bone marrow precursor cells in zinc-induced copper deficiency anemia. Am J Clin Pathol 1992;97:665–8.

9. Freycon F, Pouyau G. Rare nutritional deficiency anemia: deficiency of copper and vitamin E. Sem Hop 1983;59:488–93 [review] [in French].

10. Borgna-Pignatti C, Marradi P, Pinelli L, et al. Thiamine-responsive anemia in DIDMOAD syndrome. J Pediatr 1989;114:405–10.

11. Neufeld EJ, Mandel H, Raz T, et al. Localization of the gene for thiamine-responsive megaloblastic anemia syndrome, on the long arm of chromosome 1, by homozygosity mapping. Am J Hum Genet 1997;61:1335–41.

12. May A, Bishop DF. The molecular biology and pyridoxine responsiveness of X-linked sideroblastic anaemia. Haematologica 1998;83:56–70 [review].

13. May A, Fitzsimons E. Sideroblastic anaemia. Baillieres Clin Haematol 1994;7:851–79 [review].

14. Kasdan TS. Medical nutrition therapy for anemia. In Mahan LK, Escott-Stump S, eds. Krause’s Food, Nutrition & Diet Therapy, 10th ed. Philadelphia: W.B. Saunders, 2000, 796–7.

15. Lelord G, Muh JP, Barthelemy C, et al. Effects of pyridoxine and magnesium on autistic symptoms: Initial observations. J Autism Developmental Disorders 1981;11:219–29.

16. Martineau J, Garreau B, Barthelemy C, et al. Effects of vitamin B6 on averaged evoked potentials in infantile autism. Biol Psychiatr 1981;16:627–39.

17. Rimland B, Callaway E, Dreyfus P. The effect of high doses of vitamin B6 on autistic children: a double-blind crossover study. Am J Psychiatr 1978;135:472–5.

18. Rimland B. Vitamin B6 versus Fenfluramine: a case-study in medical bias. J Nutr Med 1991;2:321–2.

19. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (Vitamin B6) upon depression associated with oral contraception. Lancet 1973;1:897–904.

20. Russ CS, Hendricks TA, Chrisley BM, et al. Vitamin B-6 status of depressed and obsessive-compulsive patients. Nutr Rep Int 1983;27:867–73.

21. Gunn ADG. Vitamin B6 and the premenstrual syndrome (PMS). Int J Vitam Nutr Res 1985;(Suppl 27):213–24 [review].

22. Kleijnen J, Riet GT, Knipschild P. Vitamin B6 in the treatment of the premenstrual syndrome—a review. Br J Obstet Gynaecol 1990;97:847–52.

23. Glueck CJ, Shaw P, Land JE, et al. Evidence that homocysteine is an independent risk factor for atherosclerosis in hyperlipidemic patients. Am J Cardiol 1995;75:132–6.

24. Ubbink JB, Vermaak WJH, van der Merwe A, Becker PJ. Vitamin B12, vitamin B6, and folate nutritional status in men with hyperhomocysteinemia. Am J Clin Nutr 1993;57:47–53.

25. Ubbink JB, Vermaak WJH, ven der Merwe A, et al. Vitamin requirements for the treatment of hyperhomocysteinemia in humans. J Nutr 1994;124:1927–33.

26. Dierkes J, Kroesen M, Pietrzik K. Folic acid and vitamin B6 supplementation and plasma homocysteine concentrations in healthy young women. Int J Vitam Nutr Res 1998;68:98–103.

27. Stein JH, McBride PE. Hyperhomocysteinemia and atherosclerotic vascular disease: pathophysiology, screening, and treatment. Arch Intern Med 1998;158:1301–6.

28. McGregor D, Shand B, Lynn K. A controlled trial of the effect of folate supplements on homocysteine, lipids and hemorheology in end-stage renal disease. Nephron 2000;85:215–20.

29. Food standards: amendment of standards of identity for enriched grain products to require addition of folic acid. Fed Regist 1996;61:8781–97.

30. Jacques PF, Selhub J, Bostom AG, et al. The effect of folic acid fortification on plasma folate and total homocysteine concentrations. N Engl J Med 1999;340:1449–54.

31. Malinow MR, Duell PB, Hess DL, et al. Reduction of plasma homocyst(e)ine levels by breakfast cereal fortified with folic acid in patients with coronary heart disease. N Engl J Med 1998;338:1009–15.

32. Sahakian V, Rouse D, Sipes S, et al. Vitamin B6 is effective therapy for nausea and vomiting of pregnancy: a randomized, double-blind placebo-controlled study. Obstet Gynecol 1991;78:33–6.

33. Vutyavanich T, Wongtra-ngan S, Ruangsri R. Pyridoxine for nausea and vomiting of pregnancy: a randomized, double blind, placebo-controlled trial. Am J Obstet Gynecol 1995;173:881–4.

34. Barr W. Pyridoxine supplements in the premenstrual syndrome. Practitioner 1984;228:425–7.

35. Gunn ADG. Vitamin B6 and the premenstrual syndrome. Int J Vitam Nutr Res 1985;Suppl 27:213–24 [review].

36. Kleijnen J, Riet GT, Knipschild P. Vitamin B6 in the treatment of the premenstrual syndrome—a review. Br J Obstet Gynaecol 1990;97:847–52 [review].

37. Williams MJ, Harris RI, Deand BC. Controlled trial of pyridoxine in the treatment of premenstrual syndrome. J Int Med Res 1985;13:174–9.

38. Brush MG, Perry M. Pyridoxine and the premenstrual syndrome. Lancet 1985;i:1399 [letter].

39. Hagen I, Nesheim B-I, Tuntland T. No effect of vitamin B6 against premenstrual tension. Acta Obstet Gynecol Scand 1985;64:667–70.

40. Wyatt KM, Dimmock PW, Jones PW, Shaughn O’Brien PM. Efficacy of vitamin B-6 in the treatment of premenstrual syndrome: systematic review. BMJ 1999;318:1375–81.

41. Madigan SM, Tracey F, McNulty H, et al. Riboflavin and vitamin B-6 intakes and status and biochemical response to riboflavin supplementation in free-living elderly people. Am J Clin Nutr 1998;68(2):389–95.

42. Tolonen M, Schrijver J, Westermarck T, et al. Vitamin B6 status of Finnish elderly. Comparison with Dutch younger adults and elderly. The effect of supplementation. Int J Vitam Res 1988;58(1):73–7.

43. Deijen JB, van der Beek EJ, Orlebeke JF, et al. Vitamin B-6 supplementation in elderly men: effects on mood, memory, performance and mental effort. Psychopharmacology (Berl) 1992;109(4):489–96.

44. Kang JH, Cook N, Manson J, Buring JE, Albert CM, Grodstein F. A trial of B vitamins and cognitive function among women at high risk of cardiovascular disease. Am J Clin Nutr 2008;88:1602-10.)

45. Collipp PJ, Chen SY, Sharma RK, et al. Tryptophane metabolism in bronchial asthma. Ann Allergy 1975;35:153–8.

46. Weir MR, Keniston RC, Enriquez JI, McNamee GA. Depression of vitamin B6 levels due to theophylline. Ann Allergy 1990;65:59–62.

47. Collipp PJ, Goldzier S III, Weiss N, et al. Pyridoxine treatment of childhood bronchial asthma. Ann Allergy 1975;35:93–7.

48. Reynolds RD, Natta CL. Depressed plasma pyridoxal phosphate concentrations in adult asthmatics. Am J Clin Nutr 1985;41:684–8.

49. Sur S, Camara M, Buchmeier A, et al. Double-blind trial of pyridoxine (vitamin B6) in the treatment of steroid-dependent asthma. Ann Allergy 1993;70:141–52.

50. Fuhr JF, Farrow A, Nelson HS. Vitamin B6 levels in patients with carpal tunnel syndrome. Arch Surg 1989;124:1329–30.

51. Keniston RC, Nathan PA, Leklem JE, Lockwood RS. Vitamin B6, vitamin C, and carpal tunnel syndrome. J Occup Environ Med 1997;39:949–59.

52. Franzblau A, Rock CL, Werner RA, et al. The relationship of vitamin B6 status to median nerve function and carpal tunnel syndrome among active industrial workers. J Occup Environ Med 1996;38:485–91.

53. Smith GP, Rudge PJ, Peters TJ. Biochemical studies of pyridoxal and pyridoxal phosphate status and therapeutic trial of pyridoxine in patients with carpal tunnel syndrome. Ann Neurol 1984;15:104–7.

54. Ellis JM, Azuma J, Watanbe T, Folkers K. Survey and new data on treatment with pyridoxine of patients having a clinical syndrome including the carpal tunnel and other defects. Res Comm Chem Path Pharm 1977;17(1):165–77.

55. Ellis JM. Vitamin B6 deficiency in patients with a clinical syndrome including the carpal tunnel defect. Biochemical and clinical response to therapy with pyridoxine. Res Comm Chem Path Pharm 1976;13(4):743–57.

56. D’Souza M. Carpal tunnel syndrome: clinical or neurophysiological diagnosis. Lancet 1985;i:1104–5.

57. Driskell JA, Wesley RL, Hess IE. Effectiveness of pyridoxine hydrochloride treatment on carpal tunnel syndrome patients. Nutr Rep Internat 1986;34(4):1031–9.

58. Ellis JM. Treatment of carpal tunnel syndrome with vitamin B6. Southern Med J 1987;80(7):882–4.

59. Browning DM. Carpal tunnel syndrome: clinical or neurophysiological diagnosis? Lancet 1985;i:1104–5 [letter].

60. Smith GP, Rudge PJ, Peters TJ. Biochemical studies of pyridoxal and pyridoxal phosphate status and therapeutic trial of pyridoxine in patients with carpal tunnel syndrome. Ann Neurol 1984;15:104–7.

61. Amadio PC. Pyridoxine as an adjunct in the treatment of carpal tunnel syndrome. J Hand Surg 1985;10A(2):237–41.

62. Stransky M, Rubin A, Lava NS, Lazaro RP. Treatment of carpal tunnel syndrome with vitamin B6: a double-blind study. Southern Med J 1989;82(7):841–2.

63. Bernstein AL, Dinesen JS. Brief communication: effect of pharmacologic doses of vitamin B6 on carpal tunnel syndrome, electronencephalographic results, and pain. J Am Coll Nutri 1993;12:73–6.

64. Gaby AR. Literature review & commentary. Townsend Letter for Doctors and Patients.1990;Jun:338–9.

65. Parry G, Bredesen DE. Sensory neuropath with low-dose pyridoxine. Neurology 1985;35:1466–8.

66. Schaumburg H, Kaplan J, Windebank A, et al. Sensory neuropathy from pyridoxine abuse. N Engl J Med 1983;309(8):445–8.

67. Hallert C, Astrom J, Walan A. Reversal of psychopathology in adult celiac disease with the aid of pyridoxine (vitamin B6). Scand J Gastroenterol 1983;18:299–304.

68. Hallert C, Svensson M, Tholstrup J, Hultberg B. Clinical trial: B vitamins improve health in patients with coeliac disease living on a gluten-free diet. Aliment Pharmacol Ther 2009;29:811–6.

69. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (Vitamin B6) upon depression associated with oral contraception. Lancet 1973;1:897–904.

70. Russ CS, Hendricks TA, Chrisley BM, et al. Vitamin B-6 status of depressed and obsessive-compulsive patients. Nutr Rep Int 1983;27:867–73.

71. Gunn ADG. Vitamin B6 and the premenstrual syndrome (PMS). Int J Vitam Nutr Res 1985;(Suppl 27):213–24 [review].

72. Kleijnen J, Riet GT, Knipschild P. Vitamin B6 in the treatment of the premenstrual syndrome—a review. Br J Obstet Gynaecol 1990;97:847–52.

73. Carrero JJ, Lopez-Huertas E, Salmeron LM, et al. Daily supplementation with (n-3) PUFAs, oleic acid, folic acid, and vitamins B-6 and E increases pain-free walking distance and improves risk factors in men with peripheral vascular disease. J Nutr2005;135:1393–9.

74. Schwieger G, Karl H, Schonhaber E. Relapse prevention of painful vertebral syndromes in follow-up treatment with a combination of vitamins B1, B6, and B12. Ann NY Acad Sci 1990;585:54–62.

75. Kuhlwein A, Meyer HJ, Koehler CO. Reduced diclofenac administration by B vitamins: results of a randomized double-blind study with reduced daily doses of diclofenac (75 mg diclofenac versus 75 mg diclofenac plus B vitamins) in acute lumbar vertebral syndromes. Klin Wochenschr 1990;68:107–15 [in German].

76. Bruggemann G, Koehler CO, Koch EM. Results of a double-blind study of diclofenac + vitamin B1, B6, B12 versus diclofenac in patients with acute pain of the lumbar vertebrae. A multicenter study. Klin Wochenschr 1990;68:116–20 [in German].

77. Vetter G, Bruggemann G, Lettko M, et al. Shortening diclofenac therapy by B vitamins. Results of a randomized double-blind study, diclofenac 50 mg versus diclofenac 50 mg plus B vitamins, in painful spinal diseases with degenerative changes. Z Rheumatol 1988;47:351–62 [in German].

78. Christen WG, Glynn RJ, Chew EY, et al. Folic acid, pyridoxine, and cyanocobalamin combination treatment and age-related macular degeneration in women: the Women's Antioxidant and Folic Acid Cardiovascular Study. Arch Intern Med 2009;169:335–41.

79. Wen CP, Gershoff SN. Effects of dietary vitamin B6 on the utilization of monosodium glutamate by rats. J Nutr 1972;102:835–40.

80. Folkers K, Shizukuishi S, Scudder SL, et al. Biochemical evidence for a deficiency of vitamin B6 in subjects reacting to monosodium-L-glutamate by the Chinese restaurant syndrome. Biochem Biophys Res Commun 1981;100:972–7.

81. Sutterlin M, Bussen S, Ruppert D, Steck T. Serum levels of folate and cobalamin in women with recurrent spontaneous abortion. Hum Reprod 1997;12:2292–6.

82. Wouters MG, Boers GH, Blom HJ, et al. Hyperhomocysteinemia: a risk factor in women with unexplained recurrent early pregnancy loss. Fertil Steril 1993;60:820–5.

83. Steegers-Theunissen RP, Boers GH, Blom HJ, et al. Hyperhomocysteinaemia and recurrent spontaneous abortion or abruptio placentae. Lancet 1992;339:1122–3 [letter].

84. Quere I, Bellet H, Hoffet M, et al. A woman with five consecutive fetal deaths: case report and retrospective analysis of hyperhomocysteinemia prevalence in 100 consecutive women with recurrent miscarriages. Fertil Steril 1998;69:152–4.

85. Quere I, Mercier E, Bellet H, et al. Vitamin supplementation and pregnancy outcome in women with recurrent early pregnancy loss and hyperhomocysteinemia. Fertil Steril 2001;75:823–5.

86. Hawkins DR, Bortin AW, Runyon RP. Orthomolecular psychiatry: niacin and megavitamin therapy. Psychosomatics 1970;11:517–21 [review].

87. Hawkins DR, Bortin AW, Runyon RP. Orthomolecular psychiatry: niacin and megavitamin therapy. Psychosomatics 1970;11:517–21 [review].

88. Autry JH. Workshop on orthomolecular treatment of schizophrenia: a report. Schizophr Bull 1975:94–103.

89. Petrie WM, Ban TA. Vitamins in psychiatry. Do they have a role? Drugs 1985;30:58–65 [review].

90. Hoffer A. Megavitamin B-3 therapy for schizophrenia. Can Psychiatr Assoc J 1971;16:499–504.

91. Wittenborn JR, Weber ES, Brown M. Niacin in the long-term treatment of schizophrenia. Arch Gen Psychiatry 1973;28:308–15.

92. Newbold HL, Mosher LR. Niacin and the schizophrenic patient. Am J Psychiatry 1970;127:535–6.

93. Petrie WM, Ban TA, Ananth JV. The use of nicotinic acid and pyridoxine in the treatment of schizophrenia. Int Pharmacopsychiatry 1981;16:245–50.

94. Ananth JV, Ban TA, Lehmann HE. Potentiation of therapeutic effects of nicotinic acid by pyridoxine in chronic schizophrenics. Can Psychiatr Assoc J 1973;18:377–83.

95. Vaughan K, McConaghy N. Megavitamin and dietary treatment in schizophrenia: a randomised, controlled trial. Aust N Z J Psychiatry 1999;33:84–8.

96. Sandyk R, Pardeshi R. Pyridoxine improves drug-induced parkinsonism and psychosis in a schizophrenic patient. Int J Neurosci 1990;52:225–32.

97. Yamauchi M. Effects of L-dopa and vitamin B6 on electroencephalograms of schizophrenic patients: a preliminary report. Folia Psychiatr Neurol Jpn 1976;30:121–51.

98. Bucci L. Pyridoxine and schizophrenia. Br J Psychiatry 1973;122:240 [letter].

99. Manowitz P, Gilmour DG, Racevskis J. Low plasma tryptophan levels in recently hospitalized schizophrenics. Biol Psychiatry 1973;6:109–18.

100. Payne IR, Walsh EM, Whittenburg EJ. Relationship of dietary tryptophan and niacin to tryptophan metabolism in schizophrenics and nonschizophrenics. Am J Clin Nutr 1974;27:565–71.

101. Gilka L. Schizophrenia, a disorder of tryptophan metabolism. Acta Psychiatr Scand Suppl 1975;258:1–83.

102. Bowers MB Jr. Cerebrospinal fluid 5-hydroxyindoles and behavior after L-tryptophan and pyridoxine administration to psychiatric patients. Neuropharmacology 1970;9:599–604.

103. Levine J, Stahl Z, Sela BA, et al. Homocysteine-reducing strategies improve symptoms in chronic schizophrenic patients with hyperhomocysteinemia. Biol Psychiatry 2006;60:265–9.

104. Palazzo A, Cobe HM, Ploumis E. The effect of pyridoxine on the oral microbial populations. NY State Dent J 1959;25:303–7.

105. Hillman RW, Cabaud PG, Schenone RA. The effects of pyridoxine supplements on the dental caries experience of pregnant women. Am J Clin Nutr 1962;10:512–5.

106. Cohen A, Rubin C. Pyridoxine supplementation in the suppression of dental caries. Bull Phila County Dent Soc 1958;22:84.

107. Haugen HN. The blood concentration of thiamine in diabetes. Scand J Clin Lab Invest 1964;16:260–6.

108. Abbas ZG, Swai ABM. Evaluation of the efficacy of thiamine and pyridoxine in the treatment of symptomatic diabetic peripheral neuropathy. East African Med J 1997;74:804–8.

109. Stracke H, Lindemann A, Federlin K. A benfotiamine-vitamin B combination in treatment of diabetic polyneuropathy. Exp Clin Endocrinol Diabetes 1996;104:311–6.

110. Visalli N, Cavallo MG, Signore A, et al. A multi-centre randomized trial of two different doses of nicotinamide in patients with recent-onset type 1 diabetes (The IMDIAB VI). Diabetes Metab Res Rev 1999;15:181–5.

111. Wilson RG, Davis RE. Serum pyridoxal concentrations in children with diabetes mellitus. Pathology1977;9:95–9.

112. Davis RE, Calder JS, Curnow DH. Serum pyridoxal and folate concentrations in diabetics. Pathology1976;8:151–6.

113. McCann VJ, Davis RE. Serum pyridoxal concentrations in patients with diabetic neuropathy. Aust N Z J Med 1978;8:259–61.

114. Passariello N, Fici F, Giugliano D, et al. Effects of pyridoxine alpha-ketoglutarate on blood glucose and lactate in type I and II diabetics. Int J Clin Pharmacol Ther Toxicol1983;21:252–6.

115. Solomon LR, Cohen K. Erythrocyte O2 transport and metabolism and effects of vitamin B6 therapy in type II diabetes mellitus. Diabetes1989;38:881–6.

116. Wilson RG, Davis RE. Serum pyridoxal concentrations in children with diabetes mellitus. Pathology 1977;9:95–9.

117. Davis RE, Calder JS, Curnow DH. Serum pyridoxal and folate concentrations in diabetics. Pathology 1976;8:151–6.

118. McCann VJ, Davis RE. Serum pyridoxal concentrations in patients with diabetic neuropathy. Aust N Z J Med 1978;8:259–61.

119. Spellacy WN, Buhi WC, Birk SA. Vitamin B6 treatment of gestational diabetes mellitus. Am J Obstet Gynecol 1977;127:599–602.

120. Coelingh HJT, Schreurs WHP. Improvement of oral glucose tolerance in gestational diabetes by pyridoxine. BMJ 1975;3:13–5.

121. Spellacy WN, Buhi WC, Birk SA. The effects of vitamin B6 on carbohydrate metabolism in women taking steroid contraceptives: preliminary report. Contraception 1972;6:265–73.

122. Passariello N, Fici F, Giugliano D, et al. Effects of pyridoxine alpha-ketoglutarate on blood glucose and lactate in type I and II diabetics. Int J Clin Pharmacol Ther Toxicol 1983;21:252–6.

123. Solomon LR, Cohen K. Erythrocyte O2 transport and metabolism and effects of vitamin B6 therapy in type II diabetes mellitus. Diabetes 1989;38:881–6.

124. Rao RH, Vigg BL, Rao KSJ. Failure of pyridoxine to improve glucose tolerance in diabetics. J Clin Endocrinol Metab 1980;50:198–200.

125. Abbas ZG, Swai ABM. Evaluation of the efficacy of thiamine and pyridoxine in the treatment of symptomatic diabetic peripheral neuropathy. East African Med J 1997;74:804–8.

126. Stracke H, Lindemann A, Federlin K. A benfotiamine-vitamin B combination in treatment of diabetic polyneuropathy. Exp Clin Endocrinol Diabetes 1996;104:311–6.

127. Claussen CF, Claussen E. Antivertiginous action of vitamin B 6 on experimental minocycline-induced vertigo in man. Arzneimittelforschung 1988;38:396–9 [in German].

128. Snider B, Dietman DF. Pyridoxine therapy for premenstrual acne flare. Arch Dermatol 1974;110:130–1 [letter].

129. Joliffe N, Rosenblum LA, Sawhill J. Effects of pyridoxine (vit B6) on resistant adolescent acne. J Invest Dermatol 1942;5:143–8.

130. Braun-Falco O, Lincke H. The problem of vitamin B6/B12 acne. A contribution on acne medicamentosa. MMW Munch Med Wochenschr 1976;118(6):155–60 [in German].

131. Replogle WH, Eicke FJ. Megavitamin therapy in the reduction of anxiety and depression among alcoholics. J Orthomolec Med 1988;4:221–4.

132. Imagawa M, Naruse S, Tsuji S, et al. Coenzyme Q10, iron, and vitamin B6 in genetically-confirmed Alzheimer’s disease. Lancet 1992;340:671 [letter].

133. McIntosh EN. Treatment of women with the galactorrhea-amenorrhea syndrome with pyridoxine (vitamin B6). J Clin Endocrinol Metab 1976;42:1192–5.

134. Kidd GS, Dimond R, Kark JA, et al. The effects of pyridoxine on pituitary hormone secretion in amenorrhea-galactorrhea syndromes. J Clin Endocrinol Metab 1982;54:872–5.

135. Spiegel AM, Rosen SW, Weintraub BD, Marynick SP. Effect of intravenous pyridoxine on plasma prolactin in hyperprolactinemic subjects. J Clin Endocrinol Metab 1978;46:686–8.

136. Lehtovirta P, Ranta T, Seppala M. Pyridoxine treatment of galactorrhoea-amenorrhoea syndromes. Acta Endocrinol (Copenh) 1978;87:682–6.

137. Tolis G, Laliberte R, Guyda H, Naftolin F. Ineffectiveness of pyridoxine (B6) to alter secretion of growth hormone and prolactin and absence of therapeutic effects on galactorrhea-amenorrhea syndromes. J Clin Endocrinol Metab 1977;44:1197–9.

138. Goodenow TJ, Malarkey WB. Ineffectiveness of pyridoxine in evaluation and treatment of the hyperprolactinemic amenorrhea-galactorrhea syndrome. Am J Obstet Gynecol 1979;133:161–4.

139. Tolis G, Laliberte R, Guyda H, Naftolin F. Ineffectiveness of pyridoxine (B6) to alter secretion of growth hormone and prolactin and absence of therapeutic effects on galactorrhea-amenorrhea syndromes. J Clin Endocrinol Metab 1977;44:1197–9.

140. Lehtovirta P, Ranta T, Seppala M. Pyridoxine treatment of galactorrhoea-amenorrhoea syndromes. Acta Endocrinol (Copenh) 1978;87:682–6.

141. Kidd GS, Dimond R, Kark JA, et al. The effects of pyridoxine on pituitary hormone secretion in amenorrhea-galactorrhea syndromes. J Clin Endocrinol Metab 1982;54:872–5.

142. Stampfer MJ, Malinow R, Willett WC, et al. A prospective study of plasma homocyst(e)ine and risk of myocardial infarction in US physicians. JAMA 1992;268:877–81.

143. Bostom AG, Silbershatz H, Rosenberg IH, et al. Nonfasting plasma total homocysteine levels and all-cause and cardiobascular disease mortality in elderly Framingham men and women. Arch Intern Med 1999;159:1077–80.

144. Folsom AR, Nieto FJ, McGovern PG, et al. Prospective study of coronary heart disease incidence in relation to fasting total homocysteine, related genetic polymorphisms, and B vitamins. Circulation 1998;98:204–10.

145. Kuller LH, Evans RW. Homocysteine, vitamins, and cardiovascular disease. Circulation 1998;98:196–9 [editorial/review].

146. Stolzen berg-Solomon RZ, Miller ER III, Maguire MG, et al. Association of dietary protein intake and coffee consumption with serum homocysteine concentrations in an older population. Am J Clin Nutr 1999;69:467–75.

147. Selhub J, Jacques PF, Wilson PW, et al. Vitamin status and intake as primary determinants of homocysteinemia in an elderly population. JAMA 1993;270:2693–8.

148. Ubbink JB, Hayward WJ, van der Merwe A, et al. Vitamin requirements for the treatment of hyperhomocysteinemia in humans. J Nutr 1994;124:1927–33.

149. Manson JB, Miller JW. The effects of vitamin B12, B6, and folate on blood homocysteine levels. Ann NY Acad Sci 1992;669:197–204 [review].

150. Folsom AR, Nieto FJ, McGovern PG, et al. Prospective study of coronary heart disease incidence in relation to fasting total homocysteine, related genetic polymorphisms, and B vitamins. Circulation 1998;98:204–10.

151. Hackam DG, Peterson JC, Spence JD. What level of plasma homocyst(e)ine should be treated? Am J Hypertens 2000;13:105–10.

152. Till U, Rohl P, Jentsch A, et al. Decrease of carotid intima-media thickness in patients at risk to cerebral ischemia after supplementation with folic acid, vitamins B6 and B12. Atherosclerosis2005;181:131–5.

153. Franken DG, Boers GHJ, Blom HJ, et al. Treatment of mild hyperhomocysteinemia in vascular disease patients. Arterioscler Thromb 1994;14:465–70.

154. Ubbink JB, Vermaak WJH, van der Merwe A, et al. Vitamin requirements for the treatment of hyperhomocysteinemia in humans. J Nutr 1994;124:1927–33.

155. Ubbink JB, van der Merwe A, Vermaak WJH, Delport R. Hyperhomocysteinemia and the response to vitamin supplementation. Clin Investig 1993;71:993–8.

156. Bhagavan HN, Coleman M, Coursin DB. The effect of pyridoxine hydrochloride on blood serotonin and pyridoxal phosphate contents in hyperactive children. Pediatrics 1975;55:437–41.

157. Coleman M, Steinberg G, Tippett J, et al. A preliminary study of the effect of pyridoxine administration in a subgroup of hyperkinetic children: a double-blind crossover comparison with methylphenidate. Biol Psychiatry 1979;14:741–51.

158. Brenner A. The effects of megadoses of selected B complex vitamins on children with hyperkinesis: controlled studies with long term followup. J Learning Dis 1982;15:258–64.

159. Haslam RHA. Is there a role for megavitamin therapy in the treatment of attention deficit hyperactivity disorder? Adv Neurol 1992;58:303–10.

160. Thibault L, Roberge AG. The nutritional status of subjects with anorexia nervosa. Int J Vitam Nutr Res 1987;57:447–52.

161. Abou-Saleh MT, Coppen A. The biology of folate in depression: implications for nutritional hypotheses of the psychoses. J Psychiatr Res 1986;20:91–101 [review].

162. Beaumont PJ, Chambers TL, Rouse L, Abraham SF. The diet composition and nutritional knowledge of patients with anorexia nervosa. J Hum Nutr 1981;35:265–73.

163. Rock CL, Vasantharajan S. Vitamin status of eating disorder patients: relationship to clinical indices and effect of treatment. Int J Eat Disord 1995;18:257–62.

164. Langan SM, Farrell PM. Vitamin E, vitamin A and essential fatty acid status of patients hospitalized for anorexia nervosa. Am J Clin Nutr 1985;41:1054–60.

165. Kaye WH, Weltzin TE. Serotonin activity in anorexia and bulimia nervosa: relationship to the modulation of feeding and mood. J Clin Psychiatry 1991;52 Suppl:41–8 [review].

166. Smith KA, Fairburn CG, Cowen PJ. Symptomatic relapse in bulimia nervosa following acute tryptophan depletion. Arch Gen Psychiatry 1999;56:171–6.

167. Weltzin TE, Fernstrom MH, Fernstrom JD, et al. Acute tryptophan depletion and increased food intake and irritability in bulimia nervosa. Am J Psychiatry 1995;152:1668–71.

168. Oldman AD, Walsh AES, Salkovskis P, et al. Biochemical and behavioural effects of acute tryptophan depletion in abstinent bulimic subjects: a pilot study. Psychol Med 1995;25:995–1001.

169. Anderson IM, Parry-Billings M, Newsholme EA, et al. Dieting reduces plasma tryptophan and alters brain 5-HT function in women. Psychol Med 1990;20:785–91.

170. Mira M, Abraham S. L-tryptophan as an adjunct to treatment of bulimia nervosa. Lancet 1989;ii:1162–3 [letter].

171. Krahn D, Mitchell J. Use of L-tryptophan in treating bulimia. Am J Psychiatry 1985;142:1130 [letter].

172. Brewerton TD, Murphy DL, Jimerson DC. Testmeal responses following m-chlorophenylpiperazine and L-tryptophan in bulimics and controls. Neuropsychopharmacology 1994;11:63–71.

173. Hallert C, Astrom J, Walan A. Reversal of psychopathology in adult celiac disease with the aid of pyridoxine (vitamin B6). Scand J Gastroenterol 1983;18:299–304.

174. Bankier A, Turner M, Hopkins IJ. Pyridoxine dependent seizures—a wider clinical spectrum. Arch Dis Child 1983;58:415–8.

175. Baxter P, Griffiths P, Kelly T, et al. Pyridoxine-dependent seizures: demographic, clinical, MRI and psychometric features, and effect of dose on intelligence quotient. Develop Med Child Neurol 1996;38:998–1006.

176. Jiao FY, Gao DY, Takuma Y, et al. Randomized, controlled trial of high-dose intravenous pyridoxine in the treatment of recurrent seizures in children. Pediatr Neurol 1997;17:54–7.

177. Goutieres F, Aicardi J. Atypical presentation of pyridoxine-dependent seizures: a treatable cause of intractable epilepsy in infants. Ann Neurol 1985;17:117–20.

178. Brush MG, Perry M. Pyridoxine and the premenstrual syndrome. Lancet 1985;i:1399.

179. Smallwood J, Ah-Kye D, Taylor I. Vitamin B6 in the treatment of pre-menstrual mastalgia. Br J Clin Pract 1986;40:532–3.

180. Israelsson B, Brattstrom LE, Hultberg BL. Homocysteine and myocardial infarction. Atherosclerosis 1988;71:227–33.

181. Ridker PM, Manson JE, Buring JE, et al. Homocysteine and risk of cardiovascular disease among postmenopausal women. JAMA 1999;281:1817–21.

182. Bots ML, Launer LJ, Lindemans J, et al. Homocysteine and short-term risk of myocardial infarction and stroke in the elderly: the Rotterdam Study. Arch Intern Med 1999;159:38–44.

183. Stampfer MJ, Malinow MR, Willett WC, et al. A prospective study of plasma homocysteine and risk of myocardial infarction in US physicians. JAMA 1992;268:877–81.

184. Folsom AR, Nieto FJ, McGovern PG, et al. Prospective study of coronary heart disease incidence in relation to fasting total homocysteine, related genetic polymorphisms, and B vitamins: the Atherosclerosis Risk in Communities (ARIC) study. Circulation 1998;98:204–10.

185. Kuller LH, Evans RW. Homocysteine, vitamins, and cardiovascular disease. Circulation 1998;98:196–9 [editorial/review].

186. Nallamothu BK, Fendrick AM, Rubenfire M, et al. Potential clinical and economic effects of homocyst(e)ine lowering. Arch Intern Med 2000;160:3406–12.

187. Landgren F, Israelsson B, Lindgren A, et al. Plasma homocysteine in acute myocardial infarction: homocysteine-lowering effect of folic acid. J Intern Med 1995;237:381–8.

188. Ward M, McNulty H, McPartlin J, et al. Plasma homocysteine, a risk factor for cardiovascular disease, is lowered by physiological doses of folic acid. QJM 1997;90:519–24.

189. Lobo A, Naso A, Arheart K, et al. Reduction of homocysteine levels in coronary artery disease by low-dose folic acid combined with vitamins B6 and B12. Am J Cardiol 1999;83:821–5.

190. Voutilainen S, Lakka TA, Porkkala-Sarataho E, et al. Low serum folate concentrations are associated with an excess incidence of acute coronary events: the Kuopio Ischaemic Heart Disease Risk Factor Study. Eur J Clin Nutr 2000;54:424–8.

191. Kanter AS, Spencer DC, Steinberg MH, et al. Supplemental vitamin B and progression to AIDS and death in black South African patients infected with HIV. J Acquir Immune Defic Syndr 1999;21:252–3 [letter].

192. Butterworth RF, Gaudreau C, Vincelette J, et al. Thiamine deficiency in AIDS. Lancet 1991;338:1086.

193. Baum MK, Mantero-Atienza E, Shor-Posner G, et al. Association of vitamin B6 status with parameters of immune function in early HIV-1 infection. J Acquir Immune Defic Syndr 1991;4:1122–32.

194. Tang AM, Graham NMH, Saah AJ. Effects of micronutrient intake on survival in human immunodeficiency type 1 infection. Am J Epidemiol 1996;143:1244–56.

195. Boudes P, Zittoun J, Sobel A. Folate, vitamin B12, and HIV infection. Lancet 1990;335:1401–2.

196. Anderson RA et al. Chromium supplementation of humans with hypoglycemia. Fed Proc 1984;43:471.

197. Stebbing JB et al. Reactive hypoglycemia and magnesium. Magnesium Bull 1982;2:131–4.

198. Shansky A. Vitamin B3 in the alleviation of hypoglycemia. Drug Cosm Ind 1981;129(4):68–69,104–5.

199. Gaby AR, Wright JV. Nutritional regulation of blood glucose. J Advancement Med 1991;4:57–71.

200. Nath R, Thind SK, Murthy MSR, et al. Role of pyridoxine in oxalate metabolism. Ann NY Acad Sci 1990;585:274–84 [review].

201. Watts RW, Veall N, Purkiss P, et al. The effect of pyridoxine on oxalate dynamics in three cases of primary hyperoxaluria (with glycollic aciduria). Clin Sci 1985;69:87–90.

202. Mitwalli A, Ayiomamitis W, Grass L, Oreopoulos DG. Control of hyperoxaluria with large doses of pyridoxine in patients with kidney stones. Int Urol Nephrol 1988;20:353–9.

203. Berkow R, Talbott JH, et al. The Merck Manual of Diagnosis and Therapy, 13th ed. Rahway, NJ: Merck Sharp & Dohme, 1977, 732.

204. Gershoff SN, Prien EL. Effect of daily MgO and vitamin B6 administration to patients with recurring calcium oxalate kidney stones. Am J Clin Nutr 1967;20(5)393–9.

205. Prien EL, Gershoff SF. Magnesium oxide-pyridoxine therapy for recurrent calcium oxalate calculi. J Urol 1974;112:509–12.

206. Johansson G, Backman U, Danielson BG, et al. Effects of magnesium hydroxide in renal stone disease. J Am Coll Nutr 1982;1:179–85.

207. Gershoff SN, Prien EL. Effect of daily MgO and vitamin B6 administration to patients with recurring calcium oxalate kidney stones. Am J Clin Nutr 1967;20(5)393–9.

208. Curhan GC, Willett WC, Speizer FE, Stampfer MJ. Intake of vitamins B6 and C and the risk of kidney stones in women. J Am Soc Nephrol 1999;10:840–5.

209. Ettiniger B, Citron JT, Livermore B, Dolman LI. Chlorthalidone reduces calcium oxalate calculus recurrence but magnesium hydroxide does not. J Urol 1988;139:679–84.

210. Prien EL, Gershoff SF. Magnesium oxide-pyridoxine therapy for recurrent calcium oxalate calculi. J Urol 1974;112:509–12.

211. Will EJ, Bijvoet OL. Primary oxalosis: clinical and biochemical response to high-dose pyridoxine therapy. Metabolism 1979;28:542–8.

212. Lindberg J, Harvey J, Pak CYC. Effect of magnesium citrate and magnesium oxide on the crystallization of calcium salts in urine: changes produced by food-magnesium interaction. J Urol 1990;143:248–51.

213. Aston B. Manganese and man. J Orthomolec Psychiatry 1980;9:237–49.

214. Gaby AR. Preventing and Reversing Osteoporosis. Rocklin, CA: Prima Publishing, 1994, 88–9 [review].

215. Sato Y, Honda Y, Iwamoto J, et al. Effect of folate and mecobalamin on hip fractures in patients with stroke: a randomized controlled trial. JAMA 2005;293:1082–8.

216. Sawka AM, Ray JG, Yi Q, et al. Randomized clinical trial of homocysteine level lowering therapy and fractures. Arch Intern Med 2007;167:2136–9.

217. Baker AB. Treatment of paralysis agitans with vitamin B6. JAMA 1941;116:2484.

218. Pfeiffer R, Ebadi M. On the mechanism of the nullification of CNS effects of L-DOPA by pyridoxine in Parkinsonian patients. J Neurochem 1972;19(9):2175–81.

219. Leon AS, Spiegel HE, Thomas G, Abrams WB. Pyridoxine antagonism of levodopa in parkinsonism. JAMA 1971;218(13):1924–7.

220. Mars H. Metabolic interactions of pyridoxine, levodopa, and carbidopa in Parkinson’s disease. Trans Am Neurol Assoc 1973;98:241–5.

221. Kaufman G. Pyridoxine against amiodarone-induced photosensitivity. Lancet 1984;i:51–2 [letter].

222. Ross JB, Moss MA. Relief of the photosensitivity of erythropoietic protoporphyria by pyridoxine. J Am Acad Dermatol 1990;22:340–2.

223. Vinogradov VV, Tarasov IuA, Tishin VS, et al. Thiamin prevention of the corticosteroid reaction after surgery. Probl Endokrinol 1981;27:11–6 [in Russian].

224. Lettko M, Meuer S. Vitamin B-induced prevention of stress-related immunosuppression. Ann NY Acad Sci 1990;585:513–5.

225. Leeda M, Riyazi N, de Vries JI, et al. Effects of folic acid and vitamin B6 supplementation on women with hyperhomocysteinemia and a history of preeclampsia or fetal growth restriction. Am J Obstet Gynecol 1998;179:135–9.

226. Powers RW, Evans RW, Majors AK, et al. Plasma homocysteine concentration is increased in preeclampsia and is associated with evidence of endothelial activation. Am J Obstet Gynecol 1998;179:1605–11.

227. Rajkovic A, Catalano PM, Malinow MR. Elevated homocyst(e)ine levels with preeclampsia. Obstet Gynecol 1997;90:168–71.

228. Laivuori H, Kaaja R, Turpeinen U, et al. Plasma homocysteine levels elevated and inversely related to insulin sensitivity in preeclampsia. Obstet Gynecol 1999;93:489–93.

229. Sorensen TK, Malinow MR, Williams MA, et al. Elevated second-trimester serum homocyst(e)ine levels and subsequent risk of preeclampsia. Gynecol Obstet Invest 1999;48:98–103.

230. Powers RW, Evans RW, Majors AK, et al. Plasma homocysteine concentration is increased in preeclampsia and is associated with evidence of endothelial activation. Am J Obstet Gynecol 1998;179:1605–11.

231. Ray JG, Laskin CA. Folic acid and homocyst(e)ine metabolic defects and the risk of placental abruption, pre-eclampsia and spontaneous pregnancy loss: A systematic review. Placenta 1999;20:519–29 [review].

232. Sorensen TK, Malinow MR, Williams MA, et al. Elevated second-trimester serum homocyst(e)ine levels and subsequent risk of preeclampsia. Gynecol Obstet Invest 1999;48:98–103.

233. Roberts JM. Endothelial dysfunction in preeclampsia. Semin Reprod Endocrinol 1998;16:5–15.

234. Hayman R, Brockelsby J, Kenny L, Baker P. Preeclampsia: the endothelium, circulating factor(s) and vascular endothelial growth factor. J Soc Gynecol Investig 1999;6:3–10.

235. Lyall F, Greer IA. The vascular endothelium in normal pregnancy and pre-eclampsia. Rev Reprod 1996;1:107–16.

236. Roberts JM, Redman CWG. Pre-eclampsia: more than pregnancy-induced hypertension. Lancet 1994;341:1447–54.

237. Taylor RN, de Groot CJ, Cho YK, Lim KH. Circulating factors as markers and mediators of endothelial cell dysfunction in preeclampsia. Semin Reprod Endocrinol 1998;16:17–31.

238. Leeda M, Riyazi N, de Vries JI, et al. Effects of folic acid and vitamin B6 supplementation on women with hyperhomocysteinemia and a history of preeclampsia or fetal growth restriction. Am J Obstet Gynecol 1998;179:135–9.

239. Wachstein M, Graffeo LW. Influence of Vitamin B6 on the incidence of preeclampsia. Obstet Gynecol 1956;8:177–80.

240. van der Dijs FP, Schnog JJ, Brouwer DA, et al. Elevated homocysteine levels indicate suboptimal folate status in pediatric sickle cell patients. Am J Hematol 1998;59:192–8.

241. Houston PE, Rana S, Sekhasaria S, et al. Homocysteine in sickle cell disease: relationship to stroke. Am J Med 1997;103:192–6.

242. Alpert MA. Homocysteine, atherosclerosis, and thrombosis. South Med J 1999;92:858–65 [review].

243. Houston PE, Rana S, Sekhasaria S, et al. Homocysteine in sickle cell disease: relationship to stroke. Am J Med 1997;103:192–6.

244. al-Momen AK. Diminished vitamin B12 levels in patients with severe sickle cell disease. J Intern Med 1995;237:551–5.

245. Lin YK. Folic acid deficiency in sickle cell anemia. Scand J Haematol 1975;14:71–9.

246. Natta CL, Reynolds RD. Apparent vitamin B6 deficiency in sickle cell anemia. Am J Clin Nutr 1984;40:235–9.

247. Alpert MA. Homocysteine, atherosclerosis, and thrombosis. South Med J 1999;92:858–65 [review].

248. van der Dijs FP, Schnog JJ, Brouwer DA, et al. Elevated homocysteine levels indicate suboptimal folate status in pediatric sickle cell patients. Am J Hematol 1998;59:192–8.

249. Rabb LM, Grandison Y, Mason K, et al. A trial of folate supplementation in children with homozygous sickle cell disease. Br J Haematol 1983;54:589–94.

250. Waterbury L. Anemia. In Barker LR, Burton JR, Zieve PD. Principles of ambulatory medicine, 4th ed. Baltimore: Williams & Wilkins, 1995, 605.

251. Kark JA, Kale MP, Tarassoff PG, et al. Inhibition of erythrocyte sickling in vitro by pyridoxal. J Clin Invest 1978;62:888–91.

252. Kark JA, Tarassoff PG, Bongiovanni R. Pyridoxal phosphate as an antisickling agent in vitro. J Clin Invest 1983;71:1224–9.

253. Flores L, Pais R, Buchanan I, et al. Pyridoxal 5’-phosphate levels in children with sickle cell disease. Am J Pediatr Hematol Oncol 1988;10:236–40.

254. Reed JD, Redding-Lallinger R, Orringer EP. Nutrition and sickle cell disease. Am J Hematol 1987;24:441–55.

255. Natta CL, Reynolds RD. Apparent vitamin B6 deficiency in sickle cell anemia. Am J Clin Nutr 1984;40:235–9.

256. Lalouschek W, Aull S, Serles W, et al. Genetic and nongenetic factors influencing plasma homocysteine levels in patients with ischemic cerebrovascular disease and in healthy control subjects. J Lab Clin Med 1999;133:575–82.

257. Ridker PM, Manson JE, Buring JE, et al. Homocysteine and risk of cardiovascular disease among postmenopausal women. JAMA 1999;281:1817–21.

258. Perry IJ. Homocysteine, hypertension and stroke. J Hum Hypertens 1999;13:289–93 [review].

259. Genest J Jr. Hyperhomocyst(e)inemia—determining factors and treatment. Can J Cardiol 1999;15:35B–38B [review].

260. Ubbink JB, Hayward WJ, van der Merwe A, et al. Vitamin requirements for the treatment of hyperhomocysteinemia in humans. J Nutr 1994;124:1927–33.

261. Manson JB, Miller JW. The effects of vitamin B12, B6, and folate on blood homocysteine levels. Ann NY Acad Sci 1992;669:197–204 [review].

262. Wang X, Qin X, Demirtas H, et al. Efficacy of folic acid supplementation in stroke prevention: a meta-analysis. Lancet 2007;369:1876–82.

263. Tkacz C. A preventive measure for tardive dyskinesia. J Int Acad Prev Med 1984;8:(5)5–8.

264. Toll N. To the editor. J Orthomolec Psychiatry 1982;11:42.

265. Makoff R. Vitamin replacement therapy in renal failure patients. Miner Electrolyte Metab 1999;25:349–51 [review].

266. Heap LC, Peters TJ, Wessely S. Vitamin B status in patients with chronic fatigue syndrome. J R Soc Med 1999;92:183–5.

267. Bell IR, Edman JS, Morrow FD, et al. Brief communication: Vitamin B1, B2, and B6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction. J Am Coll Nutr 1992;11:159–63.

268. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

269. Bell IR, Edman JS, Morrow FD, et al. Brief communication: Vitamin B1, B2, and B6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction. J Am Coll Nutr 1992;11:159–63.

270. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 83.

271. Sur S, Camara M, Buchmeier A, et al. Double-blind trial of pyridoxine (vitamin B6) in the treatment of steroid-dependent asthma. Ann Allergy 1993;70:147–52.

272. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 86.

273. Roe D, Campbell T, eds. Drugs and Nutrients: The Interactive Effects. New York: Marcel Decker, 1984, 288–9, 505–23.

274. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 86.

275. Bell IR, Edman JS, Morrow FD, et al. Brief communication: Vitamin B1, B2, and B6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction. J Am Coll Nutr 1992;11:159–63.

276. Chouinard G, Young SN, Annable L, Sourkes TL. Tryptophan-nicotinamide, imipramine and their combination in depression. Acta Psychiatr Scand 1979;59:395–414.

277. Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384–9.

278. Shaw DM, MacSweeney DA, Hewland R, Johnson AL. Tricyclic antidepressants and tryptophan in unipolar depression. Psychol Med 1975;5:276–8.

279. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

280. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

281. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 83.

282. Sur S, Camara M, Buchmeier A, et al. Double-blind trial of pyridoxine (vitamin B6) in the treatment of steroid-dependent asthma. Ann Allergy 1993;70:147–52.

283. Vukelja SJ, Baker WJ, Burris HA, et al. Pyridoxine therapy for palmar-plantar erythrodysesthesia associated with Taxotere. J Natl Cancer Inst 1993;85:432 [letter].

284. Bell IR, Edman JS, Morrow FD, et al. Brief communication: Vitamin B1, B2, and B6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction. J Am Coll Nutr 1992;11:159–63.

285. Holt GA. Food and Drug Interactions. Chicago: Precept Press, 1998, 107–8.

286. Adams PW, Folkard J, Wynn V, Seed M. Influence of oral contraceptives, pyridoxine (vitamin B6), and tryptophan on carbohydrate metabolism. Lancet 1976;1:759-64.

287. Adams PW, Rose DP, Folkard J, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraceptives. Lancet 1973;1:897-904.

288. Adams PW, Wynn V, Seed M, Folkard J. Vitamin B6, depression, and oral contraception. Lancet 1974;2:516-7.

289. Adams PW, Folkard J, Wynn V, Seed M. Influence of oral contraceptives, pyridoxine (vitamin B6), and tryptophan on carbohydrate metabolism. Lancet 1976;1:759-64.

290. Adams PW, Rose DP, Folkard J, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraceptives. Lancet 1973;1:897-904.

291. Adams PW, Wynn V, Seed M, Folkard J. Vitamin B6, depression, and oral contraception. Lancet 1974;2:516-7.

292. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

293. Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA: Third Line Press, 1997, 210–1 [review].

294. Wynn V. Vitamins and oral contraceptive use. Lancet 1975;1:561–4.

295. Holt GA. Food & Drug Interaction. Chicago: Precept Press, 1998, 197–8.

296. Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA: Third Line Press, 1997, 210–1 [review].

297. Wynn V. Vitamins and oral contraceptive use. Lancet 1975;1:561–4.

298. Berg G, Kohlmeier L, Brenner H. Effect of oral contraceptive progestins on serum copper concentration. Eur J Clin Nutr 1998;52:711–5.

299. Holt GA. Food & Drug Interaction. Chicago: Precept Press, 1998, 197.

300. Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA: Third Line Press, 1997, 210–1 [review].

301. Wynn V. Vitamins and oral contraceptive use. Lancet 1975;1:561–4.

302. Holt GA. Food & Drug Interaction. Chicago: Precept Press, 1998, 197–8.

303. Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA: Third Line Press, 1997, 210–1 [review].

304. Wynn V. Vitamins and oral contraceptive use. Lancet 1975;1:561–4.

305. Berg G, Kohlmeier L, Brenner H. Effect of oral contraceptive progestins on serum copper concentration. Eur J Clin Nutr 1998;52:711–5.

306. Holt GA. Food & Drug Interaction. Chicago: Precept Press, 1998, 197.

307. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

308. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

309. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

310. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

311. Dierkes J, Westphal S, Luley C. Serum homocysteine increases after therapy with fenofibrate or bezafibrate. Lancet 1999;354:219–20.

312. Mayer O Jr, Simon J, Holubec L, et al. Fenofibrate-induced hyperhomocysteinemia may be prevented by folate co-administration. Eur J Clin Pharmacol 2003;59:367–71.

313. Vukelja SJ, Lombardo F, James WD, Weiss RB. Pyroxidine [sic] for the palmar-plantar erythrodysesthesia syndrome. Ann Intern Med 1989;111:688–9 [letter].

314. Molina R, Fabian C, Slavik M, Dahlberg S. Reversal of palmar-plantar erythrodysesthesia (PPE) by B6 without loss of response in colon cancer patients receiving 200/mg/m2/day continuous 5-FU. Proc Am Soc Clin Oncol 1987;6:90 [abstract].

315. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

316. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 131–2.

317. Raskin NH, Rishman RA. Pyridoxine-deficiency neuropathy due to hydralazine. N Engl J Med 1965;273:1182–5.

318. McCarty DJ. Complete reversal of rheumatoid nodulosis. J Rheumatology 1991;18:736–7.

319. Bell IR, Edman JS, Morrow FD, et al. Brief communication: Vitamin B1, B2, and B6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction. J Am Coll Nutr 1992;11:159–63.

320. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

321. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

322. Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA: Third Line Press, 1997, 210–1 [review].

323. Wynn V. Vitamins and oral contraceptive use. Lancet 1975;1:561–4.

324. Holt GA. Food & Drug Interaction. Chicago: Precept Press, 1998, 197–8.

325. Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA: Third Line Press, 1997, 210–1 [review].

326. Wynn V. Vitamins and oral contraceptive use. Lancet 1975;1:561–4.

327. Berg G, Kohlmeier L, Brenner H. Effect of oral contraceptive progestins on serum copper concentration. Eur J Clin Nutr 1998;52:711–5.

328. Holt GA. Food & Drug Interaction. Chicago: Precept Press, 1998, 197.

329. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

330. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

331. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

332. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 83.

333. Sur S, Camara M, Buchmeier A, et al. Double-blind trial of pyridoxine (vitamin B6) in the treatment of steroid-dependent asthma. Ann Allergy 1993;70:147–52.

334. Roe DA. Drug-Induced Nutritional Deficiencies, 2d ed. Westport, CT: Avi Publishing, 1985, 157–8 [review].

335. Holt GA. Food & Drug Interactions. Chicago: Precept Press,1998, 183.

336. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride (vitamin B6) upon depression associated with oral contraception. Lancet 1973;I:897–904.

337. Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA: Third Line Press, 1997, 210–1 [review].

338. Wynn V. Vitamins and oral contraceptive use. Lancet 1975;1:561–4.

339. Holt GA. Food & Drug Interaction. Chicago: Precept Press, 1998, 197–8.

340. Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA: Third Line Press, 1997, 210–1 [review].

341. Wynn V. Vitamins and oral contraceptive use. Lancet 1975;1:561–4.

342. Berg G, Kohlmeier L, Brenner H. Effect of oral contraceptive progestins on serum copper concentration. Eur J Clin Nutr 1998;52:711–5.

343. Holt GA. Food & Drug Interaction. Chicago: Precept Press, 1998, 197.

344. Bell IR, Edman JS, Morrow FD, et al. Brief communication: Vitamin B1, B2, and B6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction. J Am Coll Nutr 1992;11:159–63.

345. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

346. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 203.

347. Rothschild B. Pyridoxine deficiency. Arch Intern Med 1982;142:840.

348. Heller CA, Friedman PA. Pyridoxine deficiency and peripheral neuropathy associated with long-term phenelzine therapy. Am J Med 1983;75:887–8.

349. Walter-Sack I, Klotz U. Influence of diet and nutrition status on drug metabolism. Clin Pharmacokinet 1996;31:47–64.

350. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

351. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

352. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 83.

353. Sur S, Camara M, Buchmeier A, et al. Double-blind trial of pyridoxine (vitamin B6) in the treatment of steroid-dependent asthma. Ann Allergy 1993;70:147–52.

354. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 83.

355. Sur S, Camara M, Buchmeier A, et al. Double-blind trial of pyridoxine (vitamin B6) in the treatment of steroid-dependent asthma. Ann Allergy 1993;70:147–52.

356. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

357. Bell IR, Edman JS, Morrow FD, et al. Brief communication: Vitamin B1, B2, and B6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction. J Am Coll Nutr 1992;11:159–63.

358. Dursun SM, Oluboka OJ, Devarajan S, Kutcher SP. High-dose vitamin E plus vitamin B6 treatment of risperidone-related neuroleptic malignant syndrome. J Psychopharmacol 1998;12:220–1.

359. Holt GA. Food & Drug Interactions. Chicago: Precept Press,1998, 248–49, 251–2.

360. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 256–8.

361. Freinberg N, Lite T. Adjunctive ascorbic acid administration in antibiotic therapy. J Dent Res 1957;36:260–2.

362. Shimizu T, Maeda S, Arakawa H, et al. Relation between theophylline and circulating vitamin levels in children with asthma. Pharmacology 1996;53:384–9.

363. Martinez de Haas MG, Poels PJ, de Weert CJ, et al. Subnormal vitamin B6 levels in theophylline users. Ned Tijdschr Geneeskd 1997;141:2176–9 [in Dutch].

364. Ubbink JB, Delport R, Becker PJ, Bissbort S. Evidence of a theophylline-induced vitamin B6 deficiency caused by noncompetitive inhibition of pyridoxal kinase. J Lab Clin Med 1989;113:15–22.

365. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

366. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 248–49, 251–2.

367. Young LY, Koda-Kimble MA, eds. Applied Therapeutics: The Clinical Use of Drugs. Vancouver, WA: Applied Therapeutics, 1988, 911.

368. Kahn SB, Fein SA, Brodsky I. Effects of trimethoprim on folate metabolism in man. Clin Pharmacol Ther 1968;9:550–60.

369. Young LY, Koda-Kimble MA, eds. Applied Therapeutics: The Clinical Use of Drugs. Vancouver, WA: Applied Therapeutics, 1988, 911.

370. Safrin S, Lee BL, Sande MA. Adjunctive folinic acid with trimethoprim-sulfamethoxazole for pneumocystis carinii pneumonia in AIDS patients is associated with an increased risk of therapeutic failure and death. J Infect Dis 1994;170:912–7.

371. Bell IR, Edman JS, Morrow FD, et al. Brief communication: Vitamin B1, B2, and B6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction. J Am Coll Nutr 1992;11:159–63.

372. Reinken L. The influence of antiepileptic drugs on vitamin B6 metabolism. Acta Vitaminol Enzymol 1975;291:252–4.

373. Ito M, Okuno T, Hattori H, et al. Vitamin B6 and valproic acid in treatment of infantile spasms. Pediatr Neurol 1991;7:91–6.

374. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

375. Walter-Sack I, Klotz U. Influence of diet and nutrition status on drug metabolism. Clin Pharmacokinet 1996;31:47–64.

376. Schwaninger M, Ringleb P, Winter R, et al. Elevated plasma concentrations of homocysteine in antiepileptic drug treatment. Epilepsia 1999;40:345–50.

377. Bender DA. Inhibition in vitro of the enzymes of the oxidative pathway of tryptophan metabolism and of nicotinamide nucleotide synthesis by benserazide, carbidopa and isoniazid. Biochem Pharmacol 1980;29:707–12.

378. Bender DA. Effects of benserazide, carbidopa and isoniazid administration on tryptophan-nicotinamide nucleotide metabolism in the rat. Biochem Pharmacol 1980;29:2099–2104.

379. Bender DA, Earl CJ, Lees AJ. Niacin depletion in Parkinsonian patients treated with L-dopa, benserazide and carbidopa. Clin Sci (Colch) 1979;56:89–93.

380. Trovato A, Nuhlicek DN, Midtling JE. Drug-nutrient interactions. Am Fam Physician 1991;44:1651–8.

381. Trovato A, Nuhlicek DN, Midtling JE. Drug-nutrient interactions. Am Family Phys 1991;44:1651–8.

382. Mansoor MA, Kristensen O, Hervig T, et al. Plasma total homocysteine response to oral doses of folic acid and pyridoxine hydrochloride (vitamin B6) in healthy individuals. Oral doses of vitamin B6 reduce concentrations of serum folate. Scand J Clin Lab Invest 1999;59:139–46.

383. Weir MR, Keniston RC, Enriquez JI Sr, McNamee GA. Depression of vitamin B6 levels due to gentamicin. Vet Hum Toxicol 1990;32:235–8.

384. Goldman AL, Braman SS. Isoniazid: a review with emphasis on adverse effects. Chest 1972;62:71–7 [review].

385. Mandell GL, Petri WA Jr . Antimicrobial Agents: Drugs used in the chemotherapy of tuberculosis, Mycobacterium avium complex disease and leprosy. In Goodman and Gilman’s The Pharmacological Basis of Therapeutics, 9th ed. New York: McGraw-Hill, 1996, 1158.

386. Brent J, Vo N, Kulig K, Rumack BH. Reversal of prolonged isoniazid-induced coma by pyridoxine. Arch Intern Med 1990;150:1751–3.

387. Chan TYK. Pyridoxine ineffective in isoniazid-induced psychosis. Ann Pharmacother 1999;33:1123–4 [letter].

388. McCune R, Deuschle K, McDermott W. The delayed appearance of isoniazid antagonism by pyridoxine in vivo. Am Rev Tuberculosis 1957;76:1100–5.

389. Gaby AR. Literature review & commentary. Townsend Letter for Doctors June 1990;338–9.

390. Parry G, Bredesen DE. Sensory neuropath with low-dose pyridoxine. Neurology 1985;35:1466–8.

391. House AA, Eliasziw M, Cattran DC, et al. Effect of B-vitamin therapy on progression of diabetic nephropathy. A randomized controlled trial. JAMA 2010;303:1603–9.

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