A randomized trial involving 1,030 children found that giving oral ondansetron after an emergency department visit for vomiting due to acute gastroenteritis reduced the risk of moderate-to-severe illness within 7 days.
The trial included children aged 6 months to under 18 years who presented to six pediatric emergency departments (EDs) in Canada. All received an initial dose of ondansetron in the ED. Upon discharge, caregivers were provided with either six doses of oral ondansetron or a placebo to give as needed for vomiting during the first 48 hours after enrollment.
The primary outcome was the proportion of children who developed moderate-to-severe gastroenteritis, defined by a score of 9 or higher on the modified Vesikari scale (range, 0–20).
Among 452 children in the ondansetron group with complete follow-up, 23 (5.1%) developed moderate-to-severe gastroenteritis compared with 55 of 441 (12.5%) in the placebo group. The unadjusted risk difference was –7.4 percentage points. The adjusted odds ratio was 0.50, indicating a 50% reduction in risk.
“The administration of ondansetron remained a beneficial intervention,” said lead author Stephen B. Freedman, MDCM, of the Section of Emergency Medicine, Department of Pediatrics, Alberta Children’s Hospital and Cumming School of Medicine, University of Calgary, Calgary, Canada, and colleagues.
Several secondary outcomes, including vomiting frequency and duration, were significantly improved in the ondansetron group. The number of vomiting episodes in the first 48 hours after enrollment was lower in the ondansetron group compared with the placebo group. The adjusted rate ratio was 0.76. The median time to the last vomiting episode was shorter in the ondansetron group than in the placebo group, with an adjusted rate ratio of 0.74.
Unscheduled healthcare visits within 7 days occurred in 46 of 495 children (9.3%) in the ondansetron group and 65 of 491 (13.2%) in the placebo group . Intravenous fluid administration did not differ substantially: 13 of 495 (2.6%) in the ondansetron group versus 16 of 491 (3.3%) in the placebo group.
Adverse events occurred in 35 of 497 children (7.0%) in the ondansetron group and 35 of 492 (7.1%) in the placebo group. Among participants who received at least three doses, diarrhea episodes were more frequent with ondansetron, but overall rates did not differ significantly.
Only 31.4% of children experienced vomiting after discharge. The median number of ondansetron doses used was zero, and the mean was 0.78. The study findings suggest that ondansetron, when used as needed after discharge, reduced the risk of moderate-to-severe gastroenteritis without increasing serious adverse events.
In households managing pediatric gastroenteritis, ondansetron may help reduce illness severity, though the difference in return visits to the ED was not statistically significant.
Full disclosures can be found in the published study.
