THURSDAY, Nov. 6, 2003 (HealthDayNews) -- A first trial of marijuana-derived substances to treat the symptoms of multiple sclerosis (MS) has produced results that are promising enough to warrant further investigation, British researchers report.
But that carefully hedged conclusion should not be regarded as a license for MS patients to smoke marijuana, says study leader Dr. John Zajicek, a reader in neurology 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 are reported in this week's issue of 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, there is not sufficient evidence to recommend treatment in general," says Dr. Andrew D. Goodman, director of the MS Center at the University of Rochester and deputy chief medical officer of the National Multiple Sclerosis Society. "A physician on a case-by-case basis may take this new information into account."
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.
"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."
An advisory sent by the National Multiple Sclerosis Foundation to its local affiliates says, "Individuals interested in the use of marijuana derivatives for symptoms of multiple sclerosis should consult their physicians."
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.
But while there are "interesting suggestions of some effect, the results are not entirely coherent," he says. "There needs to be further research."
More information
Learn more about MS from the National Multiple Sclerosis Society or MedlinePlus.
