Oral Ondansetron Administration in Children Seeking Emergency Department Care for Acute Gastroenteritis: A Patient-Level Propensity-Matched Analysis

Study objective: This study aimed to explore oral ondansetron usage and impact on outcomes in clinical practice. Methods: This observational study was a planned secondary analysis of 2 trials conducted in 10 US and 6 Canadian institutions between 2014 and 2017. Children 3 to 48 months old with gastroenteritis and ≥3 episodes of vomiting in the 24 hours preceding emergency department (ED) presentation were included. Oral ondansetron was administered at the discretion of the provider. The principal outcomes were intravenous fluid administration and hospitalization at the index visit and during the subsequent 72 hours and diarrhea and vomiting frequency during the 24 hours following the ED visit. Results: In total, 794 children were included. The median age was 16.0 months (interquartile range 10.0 to 26.0), and 50.1% (398/794) received oral ondansetron. In propensity-adjusted analysis (n=528), children administered oral ondansetron were less likely to receive intravenous fluids at the index visit (adjusted odds ratio [aOR] 0.50; 95% confidence interval [CI] 0.29 to 0.88). There were no differences in the frequencies of intravenous fluid administration within the first 72 hours (aOR 0.65; 95% CI 0.39 to 1.10) or hospitalization at the index visit (aOR 0.31; 95% CI 0.09 to 1.10) or the subsequent 72 hours (aOR 0.52; 95% CI 0.21 to 1.28). Episodes of vomiting (aRR 0.86; 95% CI 0.63 to 1.19) and diarrhea (aRR 1.11; 95% CI 0.93 to 1.32) during the 24 hours following ED discharge also did not differ. Conclusion: Among preschool-aged children with gastroenteritis seeking ED care, oral ondansetron administration was associated with a reduction in index ED visit intravenous fluid administration; it was not associated with intravenous fluids administered within 72 hours, hospitalization, or vomiting and diarrhea in the 24 hours following discharge.