Cannabinoids for the treatment of multiple sclerosis: no smoke without fire?

This review evaluates the most recent evidence available on the potential of cannabinoid drugs to relieve spasticity and pain in multiple sclerosis. Many different drugs are used to control the symptoms of multiple sclerosis, periods of relapse and the progression of the disease but it is in the potential management of spasticity, pain and lower urinary tract symptoms that cannabinoids have excited interest. At present, there are relatively few published, controlled clinical studies that support the efficacy of cannabinoids in this context and the evidence that is available is contradictory. On the other hand, the results of unpublished clinical trials are more encouraging and there are other major clinical trials underway. The results of animal studies are also consistent with the hypothesis that endogenous cannabinoids and their receptors are involved in the generation of spasticity and pain.