Cannabis oil extracts for chronic pain: what else can be learned from another structured prospective cohort?

Introduction: The use of medicinal cannabis for managing pain expands, although its efficacy and safety have not been fully established through randomized controlled trials. Objectives: This structured, prospective questionnaire-based cohort was aimed to assess long-term effectiveness and safety of cannabis oil extracts in patients with chronic pain. Methods: Adult Israeli patients licensed to use cannabis oil extracts for chronic pain were followed prospectively for 6 months. The primary outcome measure was change from baseline in average weekly pain intensity, and secondary outcomes were changes in related symptoms and quality of life, recorded before treatment initiation and 1, 3, and 6 months thereafter. Generalized linear mixed model was used to analyze changes over time. In addition, "responders" (>=30% reduction in weekly pain at any time point) were identified. Results: The study included 218 patients at baseline, and 188, 154, and 131 at 1, 3, and 6 months, respectively. At 6 months, the mean daily doses of cannabidiol and D9-tetrahydrocannabinol were 22.4 +/- 24.0 mg and 20.8 +/- 30.1 mg, respectively. Pain decreased from 7.9 +/- 1.7 at baseline to 6.6 +/- 2.2 at 6 months (F(3,450) = 26.22, P < 0.0001). Most secondary parameters also significantly improved. Of the 218 participants, 24% were "responders" but could not be identified by baseline parameters. "Responders" exhibited higher improvement in secondary outcomes. Adverse events were common but mostly nonserious. Conclusion: This prospective cohort demonstrated a modest overall long-term improvement in chronic pain and related symptoms and a reasonable safety profile with the use of relatively low doses of individually titrated D9-tetrahydrocannabinol and cannabidiol.