434 - Impact of Haloperidol on Emergency Department Outcomes in Pediatric Cannabis Hyperemesis Syndrome

Publication Number: 4425.434

Alizah I. Ali, UCSF Benioff Children's Hospital Oakland, fremont, CA, United States; James Naprawa, UCSF Benioff Children's Hospital Oakland, Walnut Creek, CA, United States; Nisa Atigapramoj, UCSF Benioff Children's Hospital Oakland, Oakland, CA, United States

Background: Cannabis hyperemesis syndrome (CHS) is a significant cause of emergency department utilization among adolescents. Episodic vomiting and abdominal pain often leads to recurrent emergency department and inpatient hospitalizations. Commonly used antiemetics such as ondansetron and prochlorperazine are ineffective in the treatment of this condition. Lack of recognition of CHS results in extensive workups and administration of multiple antiemetic agents. Haloperidol shows promise as a treatment option but data on its effectiveness in pediatric populations remains limited.

Objective: To evaluate the effectiveness of a clinical practice guideline (CPG) using haloperidol as the first line agent in the treatment of CHS in the emergency department of a tertiary children’s hospital.

Design/Methods: Pre-pathway cases were identified through haloperidol administration between March 2020 and November 2021, and post-pathway cases were identified between June 2022 and June 2025. Chart review confirmed the indication for treatment. Primary outcomes included hospital admission, ondansetron administration, the number of patients who improved with haloperidol, and the presence of any explicit side effects.

Results: There were 21 pre-pathway and 71 post-pathway CHS encounters. In the pre-pathway cohort, 11/21 (52.4%) patients improved with haloperidol, compared with 55/71 (77.5%) in the post-pathway group, a significantly higher proportion (z = -2.24, p = 0.025). 14/21 (66.6%) of pre-pathway patients were admitted to the hospital, which was significantly higher than that of post-pathway encounters, 22/71 (32.4%) (z=2.81, p=0.005). Ondansetron use declined from 19/21 (90.5%) pre-pathway to 29/71 (54.9%) post-pathway (z=2.97, p=0.003).  6 patients experienced dystonic reactions, all of which improved after diphenhydramine administration.

Conclusion(s): These findings support haloperidol as a practical and effective therapy for CHS in the adolescent population. After implementation of the CPG, admissions for this condition decreased significantly as did the use of multiple antiemetic agents. As antiemetics can prolong the QTc, the reduction of polypharmacy in these patients improved patient safety. The likely reason for the improvement in efficacy of haloperidol post pathway is that the dose was standardized at 2.5 mg IV. Pre-pathway, most patients received 2 mg including 2 patients who received the medication orally. 6 patients experienced a dystonic reaction supporting the use of diphenhydramine with haloperidol.