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Systematic review and meta-analysis
Oral ondansetron decreases vomiting, as well as the need for intravenous fluids and hospital admission, in children with acute gastroenteritis
  1. Deborah A Levine
  1. Department of Emergency Medicine and Pediatrics, New York University School of Medicine/Bellevue Hospital Center, New York, New York, USA
  1. Correspondence to Deborah A Levine
    New York University School of Medicine/Bellevue Hospital Center, 27th St and First Avenue, NY 10016, USA; mlevine336{at}

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Antiemetic use is common in children. The majority of paediatric practitioners prescribe antiemetics for intractable vomiting due to gastroenteritis.1 ,2 Though gastroenteritis is self-limited, vomiting is unpleasant and may lead to dehydration and hospitalisation. The review by Fedorowicz et al evaluated the clinical effects and adverse events of antiemetics in the setting of gastroenteritis.


This is an update of a review done initially in 2005, 2006 and 2008. The review includes randomised controlled studies of children aged less than 18 years, who received antiemetics orally, intravenously or rectally for vomiting as a result of gastroenteritis. The primary outcome of the review was the time from first administration of the treatment until cessation of vomiting. The secondary outcomes were parenteral satisfaction, number of patients requiring hospitalisation or intravenous rehydration during an emergency department (ED) stay and up to 72 h after discharge, mean number of episodes of vomiting, proportion of participants with cessation of vomiting, revisits to the ED, number of subjects resuming oral rehydration and adverse events. The authors searched electronic databases, hand-searched reference lists and published abstracts and contacted experts in the field. Two authors independently assessed studies for inclusion criteria and consulted a third author for disagreement resolution. Risk bias was assessed categorically, and RR with CI was calculated. Effects of missing data were tested with sensitivity analysis with worst–best scenario analysis. Data were pooled for outcomes from two or more studies with similar populations, routes of antiemetic administration and lack of heterogeneity.

The search yielded seven trials including 1020 children aged 5 months–12 years. Two new studies were not included in prior reviews. Six studies were conducted in ED. Four studies evaluated oral ondansetron; one study each used intravenous ondansetron, intravenous dexamethasone or dimenhydrinate suppository. Outcomes varied among studies. There was a risk of bias in all studies, including five studies with a high risk of bias.


The results were broken into four sections based on methodology: oral ondansetron versus placebo; intravenous ondansetron versus dexamethasone or placebo; intravenous ondansetron versus metoclopramide or placebo and dimenhydrinate versus placebo. Only one study reported the primary outcome of the review, time to complete cessation of vomiting. The data from three of the four studies comparing oral ondansetron and placebo were able to be pooled for a meta-analysis for the secondary outcomes. Compared with children who received placebo, those who received oral ondansetron had a decreased risk of hospital admission from the ED (RR 0.40, number needed to treat (NNT) 17, 95% CI 10 to 100), although there was no difference at 72 h after discharge from the ED. There was a reduction in intravenous rehydration during the ED stay (RR 0.41, NNT 5, 95% CI 4 to 8) and at 72 h (RR 0.57, NNT 6 95% CI 4 to 13). There was an increase in the proportion of patients with cessation of vomiting (RR 1.34, NNT 5, 95% CI 3 to 7). There was no difference in revisit rates or adverse events. All the oral ondansetron studies reported diarrhoea as a side effect.

One study compared intravenous ondansetron to dexamethasone and placebo and found that the RR for admission in the ondansetron group was significantly lower than the placebo group (RR 0.21, 95% CI 0.05 to 0.81). Another study compared intravenous ondansetron to metoclopramide and placebo and reported a higher proportion of patients with cessation of vomiting in the intravenous ondansetron group (58%) and the metoclopramide group (33%) versus placebo (17%). The last study compared dimenhydrinate to placebo and found that subjects in the dimenhydrinate suppository group had 0.34 days less with vomiting compared with placebo (p=0.036).


The findings in this review support the conclusions of other non-Cochrane reviews. A rigorous review by DeCamp et al pooled seven studies of approximately 750 children and found more cessation of emesis and a reduced need for intravenous rehydration and admissions in the ondansetron-treated group.3 Szajewska et al combined four trials of approximately 500 children and found less vomiting and decreased need for intravenous rehydration in ondansetron-treated subjects but no difference in hospitalisation rates or return visits.4

This review had some limitations. It included a limited number of studies, all with some heterogeneity and bias. All the studies were based in a hospital setting and may not be easily generalised to office-based practice.

The review demonstrates that antiemetics, particularly ondansetron, decrease vomiting and reduce the need for intravenous therapy and hospital admissions from the ED. An economic analysis reports that antiemetic use leads to significant monetary savings from decreased intravenous insertions and hospital admissions.5 Shortened stays in the ED can result in more patient satisfaction and decreased burden on staffing and wait times. More research is needed to determine whether there is a role for ondansetron in severe disease, as well as to fully evaluate any adverse effects.

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  • Competing interests None.

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