Efficacy of topical capsaicin for cannabinoid hyperemesis syndrome in a pediatric and adult emergency department

Introduction: Cannabinoid hyperemesis syndrome (CHS) is a clinical diagnosis characterized by symptoms of recurrent nausea, vomiting, and severe abdominal pain in the setting of chronic cannabis use. Symptoms of CHS are frequently unresponsive to standard antiemetic therapy. Topical capsaicin applied to the abdomen has been cited as a potential effective agent for CHS however robust evidence is lacking. Methods: This was a single-center retrospective cohort study to evaluate the efficacy of topical capsaicin in pediatric and adult patients presenting to the emergency department (ED) with suspected or confirmed CHS. The primary outcome assessed was if utilization of capsaicin for CHS resulted in more patients achieving an "efficacious" result, defined as only requiring <= 1 rescue medication for symptom relief after receiving capsaicin or after administration of the first agent in patients who did not receive capsaicin during their ED course. Secondary outcomes included total ED length of stay, time to discharge after administration of the reference agent (RA), proportion of patients requiring admission, total number of medication doses given for symptom relief, change in pain score and episodes of emesis, and proportion of patients returning to the ED within 24 h for the same complaint. Additional analyses were also performed to explore patient characteristics that may be predictive of capsaicin efficacy. Results: 201 patients were included in the final analysis of which 25 were <21 years old and seen in the pediatric ED. A greater proportion of patients in the capsaicin group achieved the primary outcome of efficacy as compared to patients who did not receive capsaicin (55% vs 21%, p < 0.001, unadjusted OR 1.44 [95% CI 0.586-0.820]). There were no differences in secondary outcomes except for time to discharge after administration of the RA which was shorter in the capsaicin group (3.72 vs 6.11 h, p = 0.001). Conclusion: Significantly more patients in the capsaicin group experienced efficacy compared to patients who did not. Time to discharge after administration of the reference agent was shorter for those who received capsaicin compared to patients who did not. Administration of capsaicin did not influence patients' total number of medications received or total ED length of stay. Future research is needed to determine capsaicin's efficacy when utilized earlier in therapy, ideally upon initial diagnosis of CHS, and before additional adjunct medications are administered. (C) 2021 Elsevier Inc. All rights reserved.