Vaporized cannabis versus placebo for acute migraine: A randomized, double-blind, placebo-controlled crossover trial.

Objective: To assess the efficacy of cannabis for the treatment of acute migraine. Background: Preclinical and retrospective studies suggest cannabinoids may be effective in migraine treatment. However, there have been no randomized clinical trials examining the efficacy of cannabinoids for acute migraine. Methods: In this randomized, double-blind, placebo-controlled, crossover trial, adults with migraine treated up to four separate migraine attacks, one each with vaporized (1) 6% Delta9-tetrahydrocannabinol (THC) (THC-dominant), (2) 11% cannabidiol (CBD) (CBD-dominant), (3) 6% THC + 11% CBD, and (4) placebo cannabis flower in a randomized order. Washout period between treated migraine attacks was >/=1 week. The primary endpoint was pain relief, and secondary endpoints were pain freedom and most bothersome symptom freedom, all assessed at 2-h post-vaporization. Results: Ninety-two participants were enrolled and randomized, and 247 migraine attacks were treated. THC + CBD was superior to placebo at achieving pain relief (67.2% vs. 46.6%, odds ratio [95% confidence interval] 2.85 [1.22, 6.65], p = 0.016), pain freedom (34.5% vs. 15.5%, 3.30 [1.24, 8.80], p = 0.017), and most bothersome symptom freedom (60.3% vs. 34.5%, 3.32 [1.45, 7.64], p = 0.005) at 2 h, as well as sustained pain freedom at 24 h and sustained most bothersome symptom freedom at 24 and 48 h. THC-dominant was superior to placebo for pain relief (68.9% vs. 46.6%, 3.14 [1.35, 7.30], p = 0.008) but not pain freedom or most bothersome symptom freedom at 2 h. CBD-dominant was not superior to placebo for pain relief, pain freedom, or most bothersome symptom freedom at 2 h. There were no serious adverse events. Conclusion: Acute migraine treatment with 6% THC + 11% CBD was superior to placebo at 2-h post-treatment with sustained benefits at 24 and 48 h.