Effect of Ondansetron on the Incidence of Vomiting Associated With Ketamine Sedation in Children: A Double-Blind, Randomized, Placebo-Controlled Trial

Study objective We investigate the effect of ondansetron on the incidence of vomiting in children who receive intravenous (IV) ketamine for procedural sedation and analgesia in the emergency department (ED). Methods In this double-blind, randomized, placebo-controlled trial in a children's hospital ED, patients receiving IV ketamine (1 mg/kg) for ED procedures were randomized to receive either IV ondansetron (0.15 mg/kg; maximum 4 mg) or identical placebo. We recorded whether vomiting occurred in the ED postsedation or up to 12 hours after discharge with telephone follow-up and compared ED length of stay and parental satisfaction. Results One hundred twenty-seven children were randomized to placebo and 128 to ondansetron. The groups were similar in age, sex, and fasting duration. ED vomiting was less common with ondansetron: 6 of 128 (4.7%) versus 16 of 127 (12.6%), P =.02, difference 7.9% (95% confidence interval 1.1% to 14.7%), number needed to treat 13. Follow-up was successful in 82.7%, with vomiting in the ED or after discharge less frequent with ondansetron: 10 of 128 (7.8%) versus 24 of 127 (18.9%), P =.01, difference 11.1% (95% confidence interval 2.7% to 19.5%), number needed to treat 9. ED length of stay and parental satisfaction were similar between groups. Conclusion IV ondansetron significantly reduces the incidence of vomiting associated with IV ketamine procedural sedation in children.