Oral cannabinoid for the prophylaxis of chemotherapy-induced nausea and vomiting—a systematic review and meta-analysis

Introduction Chemotherapy-induced nausea and vomiting (CINV) is a burdensome adverse event frequently associated with chemotherapy treatment of cancer. Evidence suggests that cannabinoid CB2 receptors are present in brainstem neurons, and thus, there may exist a role for cannabinoids to counter CINV. The aim of this paper is to conduct a systematic review and meta-analysis of the efficacy and safety of oral cannabinoids compared with other treatments as documented in randomized controlled trials (RCTs). Methods A literature search was conducted using Ovid MEDLINE up until December 31, 2018; Embase Classic and Embase up until 2018 week 53; and Cochrane Central Register of Controlled Trials up until November 2018. Study data were extracted and included in this meta-analysis if they reported on at least one of the following efficacy endpoints: no nausea and no vomiting, no nausea, and no vomiting. The Mantel-Haenszel method and random effects analysis model were used, to generate odds ratio (OR) and accompanying 95% confidence intervals (CI). Results In the setting of prophylactic treatment against both nausea and vomiting, oral cannabinoid was more efficacious than placebo or other studied antiemetic treatments. When controlling for vomiting, oral cannabinoid was equally as efficacious as others. Against nausea, oral cannabinoid was equally as effective as other treatments. A greater percentage of patients administered oral cannabinoid for CINV experienced dysphoria, euphoria, and sedation. Conclusion Although there exists some evidence suggesting that oral cannabinoids may have a role in controlling for emesis from a neurophysiological perspective, these conclusions are currently not mirrored in the published RCTs to date. However, there exists only a limited number of RCTs, comparisons with older treatment regimens and a lack of standard reporting practice across published literature. Further RCTs should investigate the efficacy and safety of oral cannabinoids, to secure a better picture of the efficacy of oral cannabinoids against CINV.