The day-to-day lives of some multiple sclerosis patients are impeded by motor control disorders, or spasticity, for which there is no known satisfactory drug treatment.

Traditional drugs (myorelaxants, baclofen, botulinum toxin, etc.) have many limitations.

In patients for whom these drugs offer little relief, a marketing authorisation has been granted in France for a mouth spray containing a mixture of cannabis extracts, delta-9-tetrahydrocannabinol and cannabidiol.

The addition of cannabis extracts to a traditional drug treatment reduces spasticity in around 10% of patients. There was no noticeable improvement in the other symptoms, such as motor ability or walking difficulties.

The main adverse effects are mental (drowsiness, dizziness, other sometimes severe effects), which are reversible when the treatment is halted, and a risk of addiction. The potential for abuse increases above the level of 16 sprays a day. Treatment during pregnancy exposes the newborn baby to cannabis withdrawal syndrome.

Testing the treatment for four weeks makes it possible to target the patients who will derive a long-term benefit, and to avoid exposing those who do not to adverse mental effects.

When the treatment is continued for longer than a few weeks, it is advisable to re-assess its harm-benefit balance on a regular basis.

©Prescrire 1 June 2014

"Delta-9-tetrahydrocannabinol + cannabidiol. A reasonable option for some patients with multiple sclerosis" Prescrire Int 2014; 23 (150): 145-148. (Pdf, subscribers only).