Cannabidiol as an Adjunct to Botulinum Toxin in Blepharospasm – A Randomized Pilot Study

Abstract

Purpose: The purpose of this study was to evaluate the safety and efficacy of low dose cannabidiol (CBD; Epidiolex) as adjunctive therapy for idiopathic adult-onset blepharospasm (BPS), as well as develop a novel objective assessment methodology to gauge response. Methods: Prospective, randomized, double-masked, placebo-controlled crossover design of 6 months duration of 12 patients with BPS undergoing routine maximal botulinum toxin (BTX) therapy and experiencing breakthrough symptoms. Participants received their standard BTX every 3 months and were randomized to group A = CBD daily in cycle 1, followed by placebo in cycle 2 or group B = placebo followed by CBD. Videos recorded at days 0, 45, and 90 of each cycle were analyzed to quantify eyelid kinematics. The Jankovic Rating Scale (JRS) was used to provide a clinical rating. Results: All 12 patients completed the study without adverse events. CBD decreased median eyelid closure amplitude by 19.1% (−1.66 mm, confidence interval [CI]=−3.19 to−0.14 mm, P=0.03), decreased median eyelid closure duration by 15.8% (−18.35 ms, CI=−29.37 to−7.32 ms, P=0.001), and increased themaximum eyelid closure velocity by 34.8% (−13.26 mm/ms, CI=−20.93 to −5.58 mm/ms, P = 0.001). The JRS showed a 0.5 reduction in severity and frequency, which was not statistically significant. Conclusions: Low dose CBD was safely tolerated and improved several BPS kinematic parameters. The clinical scale suggested a direction of effect but may have been underpowered. Further studies are needed to better quantify the clinical relevance. Translational Relevance: This work describes a novel assessment methodology and therapeutic approach to bBPS.