CANNABINOID HYPEREMESIS SYNDROME: PATHOPHYSIOLOGY AND TREATMENT IN THE EMERGENCY DEPARTMENT

Background: Cannabinoid hyperemesis syndrome (CHS) is a challenging clinical disorder. CHS patients frequently present to the emergency department and may require treatment for intractable emesis, dehydration, and electrolyte abnormalities. Thought to be a variant of cyclic vomiting syndrome, CHS has become more prevalent with increasing cannabis potency and use, as enabled by various states having legalized the recreational use of cannabis. Objective: This aim of this review is to investigate the pathophysiology of CHS and evaluate the published literature on pharmacologic treatment in the emergency department. This information may be helpful in providing evidence-based, efficacious antiemetic treatment grounded in knowledge of antiemetic medications' mechanisms of action, potentially precluding unnecessary tests, and reducing duration of stay. Discussion: The endocannabinoid system is a complex and important regulator of stress response and allostasis, and it is occasionally overwhelmed from excessive cannabis use. Acute episodes of CHS may be precipitated by stress or fasting in chronic cannabis users who may have pre-existing abnormal hypothalamic-pituitary-adrenal axis feedback and sympathetic nervous system response. The reasons for this may lie in the physiology of the endocannabinoid system, the pathophysiology of CHS, and the pharmacologic properties of specific classes of antiemetics and sedatives. Treatment failure with standard antiemetics is common, necessitating the use of mechanistically logical sedating agents such as benzodiazepines and antipsychotics. Conclusion: Despite the increasing prevalence of CHS, there is a limited body of high-quality research. Benzodiazepines and antipsychotics represent logical choices for treatment of CHS because of their powerful sedating effects. Topical capsaicin holds promise based on a totally different pharmacologic mechanism. Discontinuation of cannabis use is the only assured cure for CHS. (C) 2017 Elsevier Inc. All rights reserved.