The role of oral ondansetron in children with vomiting as a result of acute gastritis/gastroenteritis who have failed oral rehydration therapy: a randomized controlled trial.

STUDY OBJECTIVE: We hypothesize that ondansetron will facilitate oral rehydration therapy in children with acute gastritis or acute gastroenteritis and mild to moderate dehydration who fail initial oral rehydration therapy. We hypothesize that subjects receiving ondansetron will tolerate oral rehydration and that a lower proportion will require intravenous hydration than subjects receiving placebo, with a clinically important difference of at least 30% when comparing 2 groups of patients presenting to the ED with acute gastritis/acute gastroenteritis. Secondarily, we hypothesize that subjects receiving ondansetron will have a lower proportion requiring admission, fewer episodes of vomiting and diarrhea, and fewer revisits.

METHODS: This double-blind, placebo-controlled, prospective, randomized trial enrolled a convenience sample of subjects 1 to 10 years old, with acute gastritis or acute gastroenteritis, who failed oral rehydration therapy in the emergency department (ED). Subjects received a weight-based dose of ondansetron (0.15 mg/kg of the orally dissolving tablet) or placebo, and oral rehydration therapy was reattempted 30 minutes later. If a subject vomited or refused to drink, he or she was considered a failed oral rehydration therapy and received IV hydration [corrected] If a subject tolerated adequate oral rehydration therapy, he or she was discharged. Parents completed symptom diaries and were contacted by telephone for follow-up. We used the chi(2) test to compare the proportions of subjects requiring IV hydration [corrected] in each group.

RESULTS: We enrolled 106 subjects: 51 received ondansetron and 55 received placebo. Eleven of 51 (21.6%; 95% confidence interval [CI] 11.3% to 35.3%) of subjects who received ondansetron required intravenous hydration and 30 of 55 (54.5%; 95% CI 40.6% to 68%) of placebo subjects required intravenous hydration (p <0.001) for a difference of 32.9% (95% CI 14.54% to 48.37%). Admission rates were 5.9% (3/51) with ondansetron and 12.7% (7/55) with placebo.

CONCLUSION: In subjects with acute gastritis/acute gastroenteritis and mild to moderate dehydration who failed initial oral rehydration therapy, the proportion of children who received intravenous hydration was smaller in the ondansetron group than in the placebo group.