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Am Fam Physician. 2020;102(1):51-52

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Clinical Question

What is the best antiemetic for vomiting in children with acute gastroenteritis?

Evidence-Based Answer

Oral ondansetron (Zofran) may be given to children presenting to the emergency department with vomiting and mild to moderate dehydration from acute gastroenteritis. It reduces hospital admissions and the need for intravenous hydration. (Strength of Recommendation: A, based on a meta-analysis of moderate-quality randomized controlled trials [RCTs] and a subsequent RCT.)

Evidence Summary

Two systematic reviews1,2 and an RCT3 evaluating oral ondansetron in children with vomiting from acute gastroenteritis in the emergency department setting found that it improved multiple outcomes. Children diagnosed with mild to moderate dehydration (n = 465) received ondansetron at varying dosages based on weight. Ondansetron reduced hospital admissions (relative risk [RR] = 0.4; 95% CI, 0.19 to 0.87) and the need for intravenous hydration (RR = 0.41; 95% CI, 0.29 to 0.59), and it decreased the failure rate of oral hydration. Those who received ondansetron were more likely to stop vomiting (RR = 1.33; 95% CI, 1.19 to 1.49) but were not less likely to return for further care. The studies were rated as moderate quality. Three studies included in one of the systematic reviews1 reported significantly increased diarrhea in children taking ondansetron (P < .05), but they did not quantify the difference between the treatment and placebo groups. A subsequent RCT (N = 176) found that ondansetron use led to significantly fewer failures of oral rehydration (12 of 82 children receiving ondansetron vs. 24 of 83 children receiving placebo; P = .04).3

A systematic review of RCTs comparing antiemetics with placebo in children presenting to the emergency department with acute gastroenteritis found some benefit from dimenhydrinate rectal suppositories and oral granisetron (Kytril).4 One of the RCTs (n = 208) found that dimenhydrinate slightly reduced days of continued vomiting (0.34 fewer days; 95% CI, −0.66 to −0.02; P = .036). Another RCT (n = 159) found that children treated with oral granisetron had less vomiting at 24 hours (92.5% vs. 79.7%; P = .02), but there was no difference at 48 or 72 hours. There was no benefit from treatment with intravenous metoclopramide (one RCT; n = 24) or intravenous dexamethasone (one RCT; n = 85). A mixed-treatment comparison determined that ondansetron was the most effective agent for reducing vomiting (odds ratio = 4.54; 95% CI, 2.45 to 8.44; P < .01).

An RCT comparing dimenhydrinate with placebo in hospitalized children with acute gastroenteritis (N = 200) found no difference in the number of vomiting episodes.5 Another RCT comparing ondansetron, domperidone (not approved by the U.S. Food and Drug Administration [FDA] but available through the FDA's expanded access program), and placebo in children with acute gastroenteritis in the emergency department setting (N = 356) found that both agents reduced the need for intravenous rehydration (ondansetron RR = 0.41; 98.6% CI, 0.20 to 0.83; domperidone RR = 0.48; 98.6% CI, 0.31 to 0.74).6

Recommendations from Others

Guidelines from the European Society for Paediatric Gastroenterology Hepatology and Nutrition and the European Society for Paediatric Infectious Diseases state that ondansetron may be effective in young children with vomiting related to acute gastroenteritis, but that more information is needed about its safety in this population.7 Guidelines from the Federation of International Societies of Paediatric Gastroenterology, Hepatology and Nutrition state that ondansetron is effective in reducing vomiting and may help avoid hospital admission, but it is associated with QT prolongation and severe cardiac arrhythmias and carries warnings by the FDA and the European Medicines Agency.8 The groups recommended against the use of metoclopramide because of adverse effects and against the use of domperidone because it is ineffective.

Copyright © Family Physicians Inquiries Network. Used with permission.

Help Desk Answers provides answers to questions submitted by practicing family physicians to the Family Physicians Inquiries Network (FPIN). Members of the network select questions based on their relevance to family medicine. Answers are drawn from an approved set of evidence-based resources and undergo peer review. The strength of recommendations and the level of evidence for individual studies are rated using criteria developed by the Evidence-Based Medicine Working Group (

The complete database of evidence-based questions and answers is copyrighted by FPIN. If interested in submitting questions or writing answers for this series, go to or email:

This series is coordinated by John E. Delzell Jr., MD, MSPH, associate medical editor.

A collection of FPIN’s Help Desk Answers published in AFP is available at

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