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Ondansetron in childhood gastroenteritis

Three Part Question

In [children with vomiting due to viral gastroenteritis] does [ondansetron] reduce the requirement for [IV rehydration]

Clinical Scenario

A 3 year old child presents to the emergency department with a twenty four hour history of vomiting, diarrhoea and reduced oral intake. You wonder whether giving oral ondansetron would improve the success of oral rehydration and reduce the requirement for IV rehydration.

Search Strategy

Medline via Ovid interface 1950 – week 3 November 2009 and the Cochrane library issue 4 2008
[{( or exp Ondansetron or AND (exp Gastroenteritis or or exp Vomiting or} limit to all child (0–18 years)].

Search Outcome

Four-hundred and twenty-six papers were found, of which four were relevant. The same papers have been described in a Cochrane review.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Roslund et al,
106 patients, 1-10 years old with a clinical diagnosis of acute gastritis/ gastroenteritis, mild or moderate dehydration who had failed controlled oral challenge in EDRCTProportion of children who received IV hydrationOndansetron had a significantly lower proportion of patients requiring intravenous hydration (p<0.001)Convenience sample Recruitment (investigator availability, patient refusal, physician refusal).No assessment of inter-observer variability in dehydration scoring. Inconsistent volume of oral rehydration prior to discharge. Lack of follow up diaries

Conflict of interests: GSK provided the melts for the trial
Need for a return visit for the same illnessThe patients in the ondansetron group had more vomiting (mean 0.71 vs 0.5 vomits) and diarrhoea (mean 1.76 vs 0.5 episodes) in the week post discharge

Higher rate returns to ED in ondansetron group vs placebo group)
Ramsook et al,
145 children age 6 months–12 years, with at least five episodes of vomiting in the preceding 24 h and had not received any antiemetics. Randomised to either ondansetron melt or placeboRCTFrequency of emesis during the 48 hour period after enrolmentThe only significant reduction was seen during the period in the EDSubjective illness severity. No quantification of dehydration. Inadequate sample size, Excluded missing patients in calculations at 24 and 48 hour of follow up

Conflict of interest: GSK provided funding but no further input
Rates of IV fluid administrationFewer patients required IV fluids in the ondansetron group (P=0.015)
Admission ratesAdmission rates; lower in ondansetron group: (P=0.007)
Frequency of diarrhoeaThe ondansetron group had significantly more diarrhoea than placebo.
Freedman et al,
215 patients, <10 years, at least one reported episode of non-bilious, non-bloody vomiting within the 4 h of ED triage, and at least one episode of diarrhoea during the illness with mild to moderate dehydration. Randomised to ondansetron melt or placebo RCTProportion who vomited while receiving oral rehydration therapySignificantly fewer patients vomited during oral rehydration in the ondansetron group (p<0.001Follow-up substandard, but >80% Conflicts of interest: GSK provided funding but no other input
Number of episodes of vomiting during oral rehydration therapyFewer episodes of vomiting during oral rehydration in ondansetron group. (p=<0.001)
Rate of intravenous rehydrationFewer patients in the ondansetron group received intravenous hydration (p<0.003) and the amount of intravenous fluid received (ml/kg) was also reduced
Rate of hospitalisationAdmission rates were similar in the two groups Adverse events: more episodes of diarrhoea in ondansetron group
Cubeddu et al,
36 children < age 8 hospitalised for minimum 24 h. Acute gastroenteritis with vomiting >2 episodes in an hour. Randomised to receive either intravenous ondansetron, metoclopramide or saline placebo RCTVomiting episodes within 24 hPlacebo mean vomits=5. Ondansetron=2 p=0.048Small sample size No details on randomisation procedure Study supported by GlaxoWellcome Research and Development, UK

Editor Comment

ED, emergency department; GSK, GlaxoSmithKline; RCT, randomised controlled trial.

Clinical Bottom Line

There is now evidence to suggest that there may be a place for antiemetics in children with mild/moderate dehydration as a result of viral gastroenteritis, who have failed a trial of oral rehydration therapy or when vomiting is a significant barrier to oral rehydration.


  1. Roslund, G. Hepps, T. Mcguillen, K. The Role of oral ondansetron in Children with vomiting as a result of acute gastritis/gastroenteritis who have failed oral rehydration therapy: a randomised control trial. Annals of Emergency Medicine 2008: 52 (1): 22-29.
  2. Ramsook, C. Sahagun-Carreon, I. Kozinetz, C et al. A randomised clinical trial comparing oral ondansetron with placebo in children with vomiting from acute gastroenteritis. Annals of emergency medicine: 2002: 39: (4) 397-403.
  3. Freedman, S. Adler, M. Seshadri, R et al. Oral Ondansetron for Gastroenteritis in a Paediatric Emergency Department . New England Journal of Medicine 2006: 354: 16: 1698-705.
  4. Cubeddu L, Trujillo L, Talmaciu I, et al. Antiemetic activity of ondansetron in acute gastroenteritis. Aliment Pharmacol Ther 1997;11:185–91.