[Treatment of spasticity in multiple sclerosis: new perspectives regarding the use of cannabinoids].

Spasticity remains a prevalent symptom in multiple sclerosis, with a significant associated disability and quality of life impairment. A significant improvement in therapy aimed at reducing multiple sclerosis relapses and modifying its course has been achieved in recent years. Both general and specific traditional treatments have, however, major limitations. Thus, its use in real practice is lower than expected. Cannabinoids provide a new way for therapy. A delta-9-tetrahydrocannabinol plus cannabidiol (1:1) association, administered through an oromucosal route, has been approved in several countries including Spain; it causes a specific effect on CB(1) and CB(2) receptors, with traditional psychotropic cannabis actions being minimized. Randomized, placebo-controlled trials, as well as longer-term open-label extensions, have shown a clear-cut efficacy to reduce spasticity and their associated symptoms in those patients refractory to other therapies, with a good tolerability/safety profile. No tolerance, abuse or addictive issues have been found. New studies will be needed to find out potential new cannabinoid-related therapies.