Cannabinoid, CB1 agonists in cervical dystonia: Failure in a phase IIa randomized controlled trial

Abstract Background Dystonia may result from reduced GABAergic transmission in the external globus pallidus (GPe). Cannabinoid CB1 agonists enhance GABA in the GPe and may therefore reduce dystonia. Objectives To determine the efficacy of the cannabinoid CB1 agonist, dronabinol, in cervical dystonia (CD). Methods Nine patients with CD were randomised to dronabinol (15 mg/d)/placebo in an 8-week crossover trial. Outcome measures included TWSTRS, visual analog scale of pain, global impression of change and adverse events (AEs). Results There was no effect of dronabinol compared to placebo on any outcome measure (all P  > 0.05, n  = 7). One subject withdrew due to AEs and one was lost to follow-up. Mild AEs were experienced by all. Conclusions Short–term use of dronabinol in CD has no benefit. Despite the study limitations, cannabinoids are unlikely to be useful in the treatment of dystonia.