P3.005: Cannabinoid Hyperemesis Syndrome in Adolescents: The Role of Aprepitant as a New Treatment Option for Rapid Symptom Relief

Introduction: Cannabinoid Hyperemesis Syndrome (CHS) is a gut–brain axis disorder causing recurrent episodes of intractable nausea, vomiting, and abdominal pain triggered by chronic cannabis use. Its rising prevalence in adolescents is attributed to increased cannabis consumption and improved recognition of hallmark symptoms. However, inconsistent diagnostic criteria and overlap with cyclical vomiting syndrome (CVS) often delay diagnosis. Untreated CHS can result in severe complications, including dehydration, electrolyte imbalances, esophageal rupture, and acute kidney injury. While the definitive treatment is cannabis cessation, symptom management remains essential and includes pharmacologic and psychosocial approaches. Though evidence is limited, benzodiazepines, haloperidol, capsaicin, and TCAs show some effectiveness, while others like ondansetron and morphine have not shown clear benefit. Aprepitant, a neurokinin-1 (NK1) receptor antagonist approved for chemotherapy-induced nausea, has shown promise in adult CVS but remains unstudied in pediatric CHS. This report presents two adolescent CHS cases where symptoms rapidly resolved with aprepitant after conventional treatments failed.

Case Description: Two adolescents with a history of chronic cannabis use presented with 2–3 days of severe, intractable nausea, vomiting, retching, and abdominal pain, preventing oral intake. Conventional treatments in the ED included ondansetron, metoclopramide, capsaicin, and IV fluids. However, these therapies failed to provide symptom relief, and the patients were admitted to the pediatric hospital medicine service, where the ED treatments were continued; haloperidol was also given to one patient. No improvement was noted in either patient; neither could tolerate even sips of water. Given persistent symptoms, aprepitant was administered. Within hours, both patients tolerated oral intake and were discharged the next day without needing further antiemetics. No readmissions have occurred to date.

Discussion: CHS poses a significant healthcare burden, with recurrent ED visits and often prolonged hospitalizations. Its pathophysiology involves desensitization of cannabinoid receptors due to chronic THC exposure, disrupting emetogenic neurotransmitter balance. Aprepitant blocks substance P at NK1 receptors in the brainstem, mitigating vomiting. While demonstrating effectiveness in pediatric CVS, its role in CHS has not been defined. Our experience aligns with studies showing rapid symptom resolution in refractory CVS and isolated adult CHS cases. Both adolescents failed standard antiemetics, but improved quickly and durably with aprepitant, suggesting it may be a viable first-line option. Pediatric dosing is currently based on chemotherapy and CVS guidelines; further studies are needed to evaluate aprepitant’s efficacy compared to current first-line treatments and ideal dosing in adolescent CHS.

Conclusion: Aprepitant may offer a safe, fast-acting alternative treatment for adolescents with CHS. To our knowledge, this report represents the first documented use of aprepitant in pediatric CHS, and suggests its potential as a first-line therapy. Given the increasing prevalence of CHS, early consideration of aprepitant may improve outcomes, decrease hospitalizations, and revolutionize the management of this debilitating condition.