Pharmacologic Treatment of Cannabinoid Hyperemesis Syndrome: A Systematic Review.

Cannabinoid hyperemesis syndrome (CHS) has become more prevalent with increasing cannabis use. CHS is often resistant to standard antiemetics. The objective of this study is to review the current evidence for pharmacologic treatment of CHS. Medline, PsycINFO, DARE, OpenGrey, Google Scholar, and the Cochrane Library were searched from inception to February 2017. Articles were selected and reviewed independently. Evidence was graded using Oxford Center for Evidence-Based Medicine guidelines. The search resulted in 1262 articles with 63 of them eligible for inclusion (205 human subjects). There were 4 prospective level-2, 3 retrospective level-3 studies, 12 level-4 case series, and 44 level-5 case reports. Among level-2 studies (64 subjects), tricyclic antidepressants (TCAs) and lorazepam were discussed as effective long- and short-term treatments, respectively, in two studies. Ondansetron, promethazine, diphenhydramine, and opioids were also mentioned, but the authors did not comment on their efficacy. Among level-3 studies (43 subjects), one reported effective treatment with antiepileptics zonisamide and levetiracetam, but not TCAs. Another reported favorable response to morphine, ondansetron, and lorazepam but did not specify the actual number of patients receiving specific treatment. Among the level-4 case series (54 subjects), benzodiazepines, haloperidol, and capsaicin were reported as helpful. For level-5 case reports (44 subjects), benzodiazepines, metoclopramide, haloperidol, ondansetron, morphine, and capsaicin were reported as effective. Effective treatments mentioned only once included fentanyl, diazepam, promethazine, methadone, nabilone, levomepromazine, piritramide, and pantoprazole. Hot showers and baths were cited in all level-4 and -5 articles as universally effective. High-quality evidence for pharmacologic treatment of CHS is limited. Benzodiazepines, followed by haloperidol and capsaicin, were most frequently reported as effective for acute treatment, and TCAs for long-term treatment. As the prevalence of CHS increases, future prospective trials are greatly needed to evaluate and further define optimal pharmacologic treatment of patients with CHS.