Medical marijuana has a variety of potential uses. For multiple sclerosis patients, I found 12 clinical trials listed at http://clinicaltrials.gov involving marijuana for the treatment of muscle spasticity or neuropathic pain. The drug forms include Sativex, Marinol, smoked cannabis, and standardized cannabis extract.
Spasticity is a common symptom of multiple sclerosis. It is characterized by an involuntary increase in muscle tone or rapid muscle contractions. Neuropathic pain is associated with many conditions. Inflammation of the neurons has been reported to be a possible cause of symptoms in multiple sclerosis and other autoimmune conditions.
Drugs currently in use provide symptom relief for some patients with multiple sclerosis, but are not effective for everyone. Side effects further limit their usefulness. Marijuana is commonly used as an alternative therapy. Studies with animal models suggest that the cannabis ingredients may provide neuroprotective and anti-inflammatory benefits to reduce symptoms.
Tetrahydrocannabinol (THC) and cannabidiol (CBD) are two ingredients of marijuana which are available in the prescription drug Sativex, which is approved for use in the United Kingdom but still in clinical trials in the United States. A recent review article reports that the combination may reduce symptoms of spasticity in patients with multiple sclerosis. This conclusion is based on the analysis of six double-blind, randomized, placebo-controlled trials. The authors note that careful monitoring of symptoms and side effects is important to find the optimum dose for each individual.
Synthetic THC alone is legally available in the United States in the drug Marinol. Some therapeutic benefit has been reported in multiple sclerosis patients, but the side effects were a significant concern. CBD is reported to reduce the levels of THC in the brain and produce a more tolerable treatment with less of a psychotropic side effect. Many patients report that smoked marijuana provides better therapy than THC pills. The Sativex combination drug, which is available as an oral spray, is an attempt to correct the limitations of the Marinol pill.