This antiemetic may help kids skip that trip to the hospital

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For children with gastroenteritis, a single dose of ondansetron can reduce the vomiting—without IV fluids or serious side effects.



Practice changer

Give oral ondansetron to children with acute gastroenteritis and moderate dehydration who are unable to tolerate oral rehydration to reduce the vomiting and avoid the need for intravenous (IV) hydration or hospitalization.1

Strength of recommendation

A: Meta-analysis of 6 high-quality studies

DeCamp LS, Byerley JS, Doshi N, et al. Use of antiemetic agents in acute gastroenteritis, a systematic review and meta-analysis. Arch Pediatr Adolesc Med. 2008;162:858-865.


Sarah, a 2-year-old who has been vomiting and had diarrhea for the past 2 days, is brought to your office by her parents. They tell you she’s unable to tolerate oral fluids, and vomited twice after being given small amounts of juice and soup earlier in the day. Sarah has decreased urine output, but she is not febrile and has no blood in her stools. On examination, you find mild tachycardia, dry mucous membranes, delayed capillary refill, and normal mental status.

You try giving Sarah an oral electrolyte solution, but she vomits immediately. Her parents are reluctant to take her to the emergency department for intravenous (IV) hydration, and ask if you can provide a safe and effective alternative.

Each year in the United States, pediatric gastroenteritis and dehydration are responsible for approximately 1.5 million outpatient visits2 and 150,000 to 170,000 hospital admissions.3 Oral hydration, recommended by pediatric practice guidelines2,4 and the World Health Organization,5 is safe and generally effective. But, as in Sarah’s case, emesis frequently interferes, leading to hospital admission for IV hydration.

An antiemetic with fewer adverse effects

Older antiemetic medications, such as promethazine, prochlorperazine, and metoclopramide, can cause sedation and extrapyramidal reactions. Ondansetron, a selective 5-hydroxytryptamine (5-HT3) receptor antagonist that has been used to control postoperative and chemotherapy-associated nausea and vomiting in children and adults, does not cause either problem. In recent studies of ondansetron’s effectiveness in treating children with gastroenteritis, increased diarrhea, lasting up to 48 hours after administration, was the only adverse event.1

Two earlier systematic reviews—a meta-analysis by Szajewska et al6 and a Cochrane review7—found clinical benefits of ondansetron for vomiting associated with acute gastroenteritis. But both concluded that the evidence was insufficient to recommend routine use of this drug. The meta-analysis that we review below included additional studies, and the researchers reached a different conclusion.

STUDY SUMMARY: Antiemetic decreases vomiting, hospitalization

DeCamp et al conducted a systematic review and meta-analysis of 11 prospective controlled trials that evaluated antiemetic use in children with vomiting from acute gastroenteritis.1 Six of the 11 trials focused on ondansetron;8-13 these 6 were the most recently published and of the highest quality. (The researchers found the remaining 5 trials to be of low methodological quality, with small sample sizes and inconsistent results, and concluded that the antiemetics they assessed should not be used for outpatients with gastroenteritis.) Their meta-analysis of these 6 trials is the focus of this PURL.

The ondansetron studies included a total of 745 children with vomiting and a clinical diagnosis of gastroenteritis. In 5 of the trials, patients received only 1 dose of ondansetron;8-10,12,13 in the sixth, families received additional doses of ondansetron to use at home.11 In 3 trials, patients were given oral ondansetron—a tablet placed on the tongue that dissolves in minutes. The remaining 3 used an IV formulation.8,10,13 Five trials were conducted in emergency departments (EDs),9-13 and 1 in an inpatient setting.8

Big reductions. Children who received ondansetron had significantly less vomiting (16.9% vs 37.8%) and IV fluid administration (13.9% vs 33.9%), and fewer hospital admissions (7.5% vs 14.6%) compared with patients who were given a placebo (TABLE). Diarrhea, the only adverse event to be systematically evaluated, was assessed in all but 1 of the trials.8-12 In 3 of the 5 that reported on this side effect, patients who received ondansetron had an increase in diarrhea for up to 48 hours.8,11,12

Ondansetron reduces vomiting, hospitalization, and IV fluid use

Continued vomiting (n=659)16.9%37.8%0.45 (0.33-0.62)5 (4-7)
IV fluid administration (n=489)13.9%33.9%0.41 (0.28-0.62)5 (4-8)
Hospital admission (n=662)7.5%14.6%0.52 (0.27-0.95)14 (9-44)
CI, confidence interval; IV, intravenous; NNT, number needed to treat; RR, relative risk.
Source: DeCamp LS, et al. Arch Pediatr Adolesc Med.1


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