Timolol is a beta-blocker drug used to lower blood pressure in people with hypertension, treat people after heart attacks, and prevent migraine headaches. Timolol is available alone and in a combination product used to lower blood pressure. Timolol is also available in eye drop and eye gel preparations used to lower high internal eye pressure due to glaucoma and other conditions.
Common brand names:
Betimol, Istalol, Timoptic XE
Summary of Interactions with Vitamins, Herbs, & Foods
In a group of 16 glaucoma patients treated with a timolol eye preparation, six weeks of oral coenzyme Q10 (90 mg per day) was reported to reduce timolol-induced cardiovascular side effects without affecting intraocular pressure treatment.1
Some beta-adrenergic blockers (called “nonselective” beta blockers) decrease the uptake of potassium from the blood into the cells,3 leading to excess potassium in the blood, a potentially dangerous condition known as hyperkalemia.4 People taking beta-blockers should therefore avoid taking potassium supplements, or eating large quantities of fruit (e.g., bananas), unless directed to do so by their doctor.
The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
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 new supplement with your doctor or pharmacist.
1. Takahashi N, Iwasaka T, Sugiura T, et al. Effect of coenzyme Q10 on hemodynamic response to ocular timolol. J Cardiovasc Pharmacol 1989;14:462-8.
2. Newall CA, Anderson LA, Phillipson JD. Herbal Medicines: A Guide for Health-Care Professionals. London: Pharmaceutical Press, 1996, 213-4.
3. Rosa RM, Silva P, Young JB, et al. Adrenergic modulation of extrarenal potassium disposal. N Engl J Med 1980;302:431-4.
4. Lundborg P. The effect of adrenergic blockade on potassium concentrations in different conditions. Acta Med Scand Suppl 1983;672:121-6 [review].
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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2015.
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