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.

中文翻译：

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口服大麻素预防化学疗法引起的恶心和呕吐的系统评价和荟萃分析。

引言化疗引起的恶心和呕吐（CINV）是一种繁重的不良事件，通常与化学疗法治疗癌症有关。有证据表明，大麻素CB2受体存在于脑干神经元中，因此，大麻素可能具有对抗CINV的作用。本文的目的是对口服大麻素与随机对照试验（RCT）中记录的其他治疗方法进行比较，对口服大麻素的疗效和安全性进行系统的回顾和荟萃分析。方法截至2018年12月31日，使用Ovid MEDLINE进行文献检索; Embase Classic和Embase直到2018周53; 以及截至2018年11月的Cochrane对照试验中央注册簿。如果研究数据报告了以下至少一项疗效终点，则应提取研究数据并将其包括在本荟萃分析中：没有恶心也没有呕吐，没有恶心也没有呕吐。使用了Mantel-Haenszel方法和随机效应分析模型来生成比值比（OR）和伴随的95％置信区间（CI）。结果在预防恶心和呕吐的治疗方法中，口服大麻素比安慰剂或其他研究的止吐药更有效。在控制呕吐时，口服大麻素与其他药物一样有效。对抗大麻，口服大麻素与其他疗法一样有效。口服大麻素治疗CINV的患者比例更高，出现烦躁不安，欣快感和镇静作用。结论尽管有一些证据表明从神经生理学的角度来看，口服大麻素可能在控制呕吐中起作用，到目前为止，这些结论目前尚未反映在已发布的RCT中。但是，RCT的数量有限，与较旧的治疗方案进行比较，并且在已发表的文献中缺乏标准的报告实践。进一步的RCT应研究口服大麻素的功效和安全性，以确保更好地了解口服大麻素对CINV的功效。