Efficacy and Safety of Cannabis Derivates and Their Synthetic Analogs. Overview of Systematic Reviews

The use of medicinal products derived from cannabis and its synthetic analogues has grown in recent years for various health conditions, which led to an increase in systematic reviews (SR) on the topic. The objective of this overview was to identify, synthesize, and critically appraise the evidence from SR on the benefits and harms of cannabis derivatives when used for therapeutic purposes in different health conditions. A comprehensive search was conducted to identify all relevant SR in Embase, Epistemonikos, MEDLINE, and Cochrane Database of Systematic Reviews. The inclusion criteria was SR assessing the effects of cannabis and its derivatives for any clinical condition that included only randomized controlled trials. A structured selection and extraction process was performed by two independent researchers. The methodological quality of the included SR was assessed using AMSTAR-2. This overview included 102 SR, 68.6% of which were of critically low quality and 17.6% were of high quality. There is low to moderate certainty of evidence of benefits from these interventions for ulcerative colitis, chronic non-cancer pain, Crohn's disease, multiple sclerosis, and post-chemotherapy nausea and vomiting. The results point to a lack of benefits for sleep disorders, chronic cancer pain refractory to opioids, pain related to radiotherapy, and pain in people receiving palliative care. For other conditions, the certainty of the evidence was very low or not assessed. This overview opens a broad and complex field for the development of primary studies to evaluate the effects of cannabinoids as primary or adjunctive therapy for different health conditions and reinforces the importance of safety assessment. Decision-makers and guideline developers can be guided by the results summarized in this overview. However, when making formal recommendations, it is essential to consider the quality of the SR and the certainty of the evidence identified for each outcome.