Introduction: Over the last two decades, experimental and clinical data suggest a therapeutic benefit of cannabis-based medicines for a variety of multiple sclerosis (MS) symptoms. Clinical trials, both with synthetic or plant-derived cannabinoids, have demonstrated clinical efficacy of cannabinoids for the treatment of spasticity, neuropathic pain and bladder dysfunction. Nabiximols, a 1:1 mix of delta-9-tetrahydrocanabinol and cannabidiol extract from cloned chemovars, was licensed in the UK in 2010 and has also been approved in other European countries and Canada. The European Federation of Neurological Societies recommends that cannabis should be used only as a second or third line treatment in central neuropathic pain.
Areas covered: After a brief discussion of the endocannabinoid system, this review focuses on the use of cannabis to improve MS symptoms. More specifically, the authors have analyzed clinical studies on cannabis-based medicine extract (CBME), in particular nabiximols, in spasticity, as well as pain, and bladder dysfunction in MS. The authors have considered the large randomized controlled trials examining the psychological effects associated with cannabinoids use as well as long-term follow-up studies.
Expert opinion: Despite a number of trials with very promising results, there are still concerns related to relative paucity of data on long-term safety. Also, the long-term efficacy information in terms of the control of symptoms of a disease in which the natural history is progression is sparse. Therefore, further studies are required to improve the current knowledge of nabiximols.