Objectives Acute gastroenteritis is a leading cause of pediatric emergency department (ED) visits. While ondansetron reduces vomiting, intravenous rehydration, and hospital admissions, its efficacy when initiated at triage remains unclear. We aimed to evaluate whether triage nurse-initiated administration of ondansetron in children with suspected gastroenteritis reduces the proportion of patients requiring observation following initial physician assessment.

Methods We conducted a randomized, double-blind, placebo-controlled trial in a tertiary pediatric ED in Canada. Children aged 6 months to 17 years presenting with morae than 3 episodes of vomiting in the preceding 24 hours (including 1 within 2 hours of arrival), were eligible. At triage, we randomized participants to receive liquid ondansetron or a color- and taste-matched placebo. The primary outcome was the proportion of patients requiring observation after the first physician evaluation. Secondary outcomes included post-intervention vomiting, ED length of stay, patient comfort, and 48-hour return visits. The trial was registered at ClinicalTrials.gov (NCT03052361).

Results Recruitment was stopped prematurely due to the COVID-19 pandemic. Ninety-one participants were randomized to ondansetron (n= 44) or placebo (n= 47). Overall, 40 patients (45%) were discharged immediately after the initial physician assessment, with no difference between the ondansetron and placebo groups (44% vs. 45%; absolute difference -1%, 95% CI: -20% to 19%). No significant differences were observed in all secondary outcomes.

Conclusion In this trial, triage nurse-initiated ondansetron administration did not reduce the need for ED observation in children with presumed gastroenteritis. While being underpowered, this study could inform researchers planning larger clinical trials.

The authors have declared no competing interest.

ClinicalTrials.gov (NCT03052361)

Study financially supported by a grant from the Canadian Association of Emergency Physicians (CAEP). No pharmaceutical or industry support to declare.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Our study was approved by the research Ethics Board of CHU Sainte-Justine Research Institute in Montreal, Canada. This includes approval by the ethic committee and the scientific committee. We also obtained a Non-objection letter from Health Canada.

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Funding: Study financially supported by a grant from the Canadian Association of Emergency Physicians (CAEP). No pharmaceutical or industry support to declare.

Financial Disclosure: All authors have indicated they have no financial relationships relevant to this article to disclose.

All data produced in the present study are available upon reasonable request to the authors