UMHS LOGOUniversity of Michigan
Department of Pediatrics

Evidence-Based Pediatrics Web Site

Ondansetron Combined With IV Fluids Decreases Emesis and Need for Admission in Certain Pediatric Patients With Acute Gastroenteritis.


  • In healthy pediatric patients with acute gastroenteritis, does the use of 5-HT3 receptor antagonists, compared to no antiemetic therapy, reduce vomiting and improve ED outcome?

Clinical Bottom Lines

  1. Ondansetron had a clinically significant effect on cessation of vomiting, but did not reduce the overall number of hospitalizations.1
  2. Each year 220,000 children under 5 years-old are admitted for treatment of dehydration secondary to gastroenteritis.2
  3. There is some benefit to using antiemetic therapy in patients with acute gastroenteritis, but they are not widely used due to poor side effect profile with older agents including prochlorperazine, promethazine HCl, and metoclopramide.1
  4. 5-HT3 receptor antagonists commonly used in chemotherapy and post operative patients as antiemetics have better side effect profiles than older agents.1

Summary of Key Evidence

  1. A placebo controlled, double blind, randomized trial compared the effect of 0.15mg/kg IV ondansetron as a single dose with standard IV fluid treatment compared with IV fluid treatment alone in patients aged 1 month to 22 years (mean age 5.3) with acute gastroenteritis.1
  2. Ondansetron had a clinically significant effect on cessation of vomiting.
  3. There was not a clinically significant reduction in admission for all randomized patients.
  4. However, in a subgroup analysis patients with a serum CO2 level = 15 and with no history of previous IVF bolus in 48 hours, there was a clinically significant reduction in hospital admission.1
  5. No significant difference in adverse effects between treatment and control groups, and all were mild.

Additional Comments

  • Ondansetron is a selective 5-HT3 receptor antagonist. It may affect serotonin receptors of the peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the area postrema.
  • A second study evaluated use of oral ondansetron to improve success of ORT in pediatric patients with acute gastroenteritis. It showed a reduction in the median number of further episodes of emesis, but no significant cessation of emesis.3
  • Unless the diagnosis of gastroenteritis is highly likely, cessation of emesis may delay actual diagnosis, and mask actual diagnosis.
  • Good side effect profile of ondansetron with no difference compared to control group. Side effects include headache, diarrhea, constipation, fever. Low cost of medication compared to hospital admission ($26 per dose of ondansetron compared to $1900 per admission).


  1. Reeves JJ, Shannon MW, Fleisher GR. Ondansetron decreases vomiting associated with acute gastroenteritis: a randomized, controlled trial. Pediatrics. 2002; 109:e62.
  2. American Academy of Pediatrics, Subcommittee on Acute Gastroenteritis. Practice parameter: the management of acute gastroenteritis in young children. Pediatrics. 1996; 97:424-35.
  3. Ramsook C, Sahagun-Carreon I, Kozinetz CA, Moro-Sutherland D. A randomized clinical trial comparing oral ondansetron with placebo in children with vomiting from acute gastroenteritis. Annals of Emergency Medicine. 2002;39:397-403.

CAT Author: Fred Baker, MD

CAT Appraisers: Alex Kemper, MD

Date appraised: May 19, 2003

Last updated April 24, 2006
Department of Pediatrics and Communicable Diseases
© 1998-2002 University of Michigan Health System