Ondansetron Use in the Pediatric Emergency Department and Effects on Hospitalization and Return Rates: Are We Masking Alternative Diagnoses?

Study objective: We evaluate the effect of ondansetron use in cases of suspected gastroenteritis on the proportion of hospital admissions and return visits and assess whether children who receive ondansetron on their initial visit to the pediatric emergency department (ED) for suspected gastroenteritis return with an alternative diagnosis more frequently than those who did not receive ondansetron. Methods: This is a retrospective review of visits to 2 tertiary care pediatric EDs with an International Classification of Diseases, Ninth Revision diagnosis of vomiting or gastroenteritis. A logistic regression model was developed to determine the effect of ondansetron use during the initial pediatric ED visit on hospital admission, return to the pediatric ED within 72 hours, and admission on this return visit. For patients who returned within 72 hours and were admitted, hospital discharge records were reviewed. The proportions of alternative diagnoses, defined as a hospital discharge diagnosis that was not a continuation of gastroenteritis or vomiting, were compared between the groups. Results: During the 3-year study period (2005 to 2007), 34,117 patients met study criteria. Ondansetron was used for 19,857 (58.2%) of these patients on their initial pediatric ED visit. After controlling for differences between the groups, patients who received ondansetron were admitted on their initial visit less often: odds ratio (OR) 0.47 (95% confidence interval [CI] 0.42 to 0.53). However, those who received ondansetron were more likely to return to the pediatric ED within 72 hours (OR 1.45; 95% CI 1.27 to 1.65) and be admitted on the return visit (OR 1.74; 95% CI 1.39 to 2.19). The proportions of alternative diagnoses at hospital discharge were not significantly different in the group that received ondansetron on the initial pediatric ED visit (14.9%) compared with the group that did not (22.4%) (absolute difference 7.5% [95% CI 0.5% to 16.4%). Conclusion: Ondansetron use in the pediatric ED reduces hospital admissions for suspected gastroenteritis and vomiting. However, children who receive ondansetron in the pediatric ED appear more likely to return to the pediatric ED and be admitted on this return visit than their counterparts. Furthermore, the use of ondansetron does not appear to be associated with increased risks of masking serious diagnoses in children. [Ann Emerg Med. 2010;55:415-422.]