Whither Marijuana? Medical Research Says it has Some Promise
(HealthDay News) – It would be hard to find a medical or health professional who would say that using marijuana is good for you.
In fact, study after study has demonstrated that regular marijuana use damages brain cells and the lungs.
But scientific research has also concluded that cannabis, the active ingredient in marijuana, holds the possibility that it may be helpful in treating certain diseases and conditions.
A good recent example is a study into of multiple sclerosis (MS), one of the most difficult neurological diseases to treat.
A 2003 British clinical trial of marijuana-derived substances to treat MS symptoms found that there was marked improvement in pain control and a patient’s endurance in walking.
But the carefully hedged conclusion should not be regarded as a license for MS patients to smoke marijuana, says study leader Dr. John Zajicek, a neuroscience professor at the Peninsula Medical School in Plymouth.
"I wouldn't advocate smoking marijuana under any circumstances and in any amount," Zajicek says, mostly because marijuana smoke is more damaging than tobacco smoke.
The trial, whose results were reported in The Lancet, included 630 MS patients and looked primarily at the muscle spasms that are a major problem for them. There was no difference in scores on a standard measure of spasticity for those who got a marijuana-derived cannabinoid and those who got a placebo, the researchers report.
"But in other areas, such as pain and walking time, we did find an effect," Zajicek says. "What we need to do is to build on this study. We have generated an independent network as a way to carry out more specific studies looking at different symptoms of MS."
One of the cannabinoid chemicals extracted from marijuana and used in the study is available in the United States and Canada as a prescription drug. Marinol is approved for use against the nausea and vomiting caused by cancer treatment and to improve the appetite of people infected with HIV, the virus that causes AIDS.
Legally, Marinol can be prescribed for MS patients. "But in my view, a physician on a case-by-case basis may take this new information into account," says Dr. Andrew D. Goodman, director of the MS Center at the University of Rochester and a member of the medical advisory board of the National Multiple Sclerosis Society.
Dr. Luanne M. Metz, an associate professor of clinical neurosciences at the University of Calgary in Canada and co-author of an accompanying editorial, says she might consider Marinol to treat the muscle spasticity that is a major problem for many MS patients. Muscle spaticity is a state of increased tone of a muscle, which can cause difficulty in movement.
"If I tried everything else we have and the patient still has spasticity, I would consider trying Marinol," Metz says. "I feel there is as much evidence for using this drug as for other treatments we have used."
There is some evidence that cannabinoid treatment can limit cell death in MS, Zajicek says. "And there were slightly fewer relapses in patients receiving cannabinoids," he says. "We need to know if that is a quirk or a real effect."
Neither the MS Society nor the national Multiple Sclerosis Foundation advocates use of medical marijuana. Both advise that a patient consult a physician before making any decision.
The British study is important if only because "it is the largest systematic assessment of the effects of cannabis derivatives as well as the largest study of any treatment for multiple sclerosis," Goodman says.
Another study in 2006 found further evidence that cannabis might be effective in treating MS.
Researchers from Germany and the United States concluded that the release of the endocannabionid anadamide (AEA) in injured brain tissue may act as a "gatekeeper" and create an important "negative feedback loop within the CNS (central nervous system) immune system needed to reduce the extent of the inflammatory response and to limit neurodegenerative immune reactions after primary brain damage."
This type of signaling can maintain "a protective and healthy CNS microenvironment," the researchers wrote.
In the past, both the American Medical Association (AMA) and the National Multiple Sclerosis Society have said there is not enough evidence to support the use of medical marijuana. The AMA has said that research is needed to determine if marijuana is useful in treating pain and other medical conditions.
And the U.S. Food and Drug Administration has concluded that "no sound scientific studies supported medical use of marijuana for treatment in the United States, and no animal or human data supported the safety or efficacy of marijuana for general medical use."
Yet, the scientific research continues to indicate that cannabis-derived uses might be medically sound.
The real question may be: How do you take your medicine -- in a pill or up in smoke?
On the Web
Learn more about MS from the National Multiple Sclerosis Society.
SOURCES: John Zajicek, M.D., Professor of Clinical Neuroscience, Generic Research Support, Peninsula Medical School, Plymouth, England; Andrew D. Goodman, M.D., Director, the Multiple Sclerosis Center at the University of Rochester Medical Center in Rochester, NY; Luanne M. Metz, associate professor, clinical neurosciences, University of Calgary, Canada; Nov. 8, 2003, The Lancet
Publication date: April 1, 2007
Author: Ed Edelson, HealthDay Reporter
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