“Conventional drugs have only a limited impact on spasticity associated with multiple sclerosis and are rarely satisfactory. A solution for oral transmucosal delivery (spray) containing a mixture of cannabis extracts (2.7 mg of delta-9-tetrahydrocannabinol + 2.5 mg of cannabidiol per spray) has been granted marketing authorisation in France for patients who are inadequately relieved by standard treatments. Three double-blind, placebo-controlled trials in a total of about 300 patients tested this combination, in addition to ongoing treatment, for periods of 6 to 14 weeks. Individually, none of these trials showed any tangible anti-spastic efficacy, but two combined analyses showed “response rates” of about 35% with the mixture versus about 25% with placebo. In a trial with 572 patients, the 241 patients who “responded” after 4 weeks of treatment were randomised to either continue using the cannabis extract or receive placebo. Twelve weeks later, 75% of patients using the extract were still “responders”, versus 51% of patients switched to placebo. The principal adverse effects of the cannabis extracts consist of neuropsychiatric disorders that resolve on treatment withdrawal. The potential for abuse increases with the dose and is tangible from 16 sprays per day. Pharmacokinetic interactions due to P-glycoprotein inhibition are likely. Treatment during pregnancy may lead to neonatal withdrawal symptoms. In practice, about 10% of patients in whom standard anti-spastic medications are unsatisfactory benefit from a specific effect of the cannabis extracts contained in this oral spray.”

http://www.ncbi.nlm.nih.gov/pubmed/25121144