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

Transl Vis Sci Technol. 2023 Aug 1;12(8):17. doi: 10.1167/tvst.12.8.17.


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 the maximum 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.

Trial registration: NCT04423341.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Blepharospasm* / drug therapy
  • Botulinum Toxins*
  • Cannabidiol* / therapeutic use
  • Humans
  • Pilot Projects
  • Prospective Studies


  • Cannabidiol
  • Botulinum Toxins

Associated data