Treatment of cannabinoid hyperemesis syndrome: A systematic review and treatment algorithm for consultation-liaison psychiatrists.

Background: Cannabinoid Hyperemesis Syndrome (CHS) is a cyclical vomiting syndrome associated with chronic cannabis use and is often resistant to anti-emetics. Despite increasing incidence of suspected CHS, literature regarding its treatment is limited, and there are no established treatment guidelines. Objectives: With the goal of establishing treatment guidelines for consultation-liaison (C-L) psychiatrists managing CHS, the authors systematically reviewed existing literature for pharmacologic treatment strategies using Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. With the results of the review, the authors propose a treatment algorithm for Chs. Methods: We searched PubMed, PyschINFO & PsychARTICLES, Embase, and Web of Science from inception to July 2021 to identify literature describing treatment of CHS. We included cases of CHS where patient-level data describing the treatment of CHS was available. Pharmacologic treatments were considered beneficial if the patient's nausea, hyperemesis, and urge to take hot showers resolved. Non-independent review of exclusion criteria assisted in reducing individual bias of the literature. Results: The authors identified 34 eligible articles, consisting of 63 individual cases. Among these articles and cases, capsaicin cream, antipsychotics, and benzodiazepines were reported to improve CHS more effectively than other, more frequently used anti-emetics, such as promethazine, ondansetron, and metoclopramide. Conclusion: An examination of treatment strategies for CHS can allow for more effective care while providing a foundation for further research in treatment. This proposed algorithm is designed to aid in establishing treatment strategies for C-L psychiatrists who assist with managing CHS for patients in general medical settings. The goal of this research is to establish evidence-based treatment guidelines for C-L psychiatrists who are managing patients with CHS in general medical settings. Recognizing the limitations of this algorithm being based on case reports adds to the necessity of further research in this area. Registration: PROSPERO (https://www.crd.york.ac.uk/PROSPERO/view/CRD42021254888) registration number CRD42021254888.