The dose-response relationship of ondansetron in preventing postoperative emesis in pediatric patients undergoing ambulatory surgery

Background: Postoperative nausea and vomiting is a distressing anesthetic complication that may delay discharge after ambulatory surgery. Effective prophylaxis for postoperative nausea and vomiting can be achieved in adults with lower doses of ondansetron, a 5-hydroxytryptamine subtype 3 receptor antagonist, compared with chemothera-induced emesis. However, the doses of ondansetron used in preventing postoperative nausea and vomiting in children are based on data from chemotherapy-induced emesis. The dose-related efficacy of intravenous ondansetron in the prophylaxis of post-operative emesis in the pediatric outpatient population was Methods: In a double-blind, randomized placebo-controlled study, 130 patients (mean age 5.7 + 3.4 yr) received placebo, 10, 50, or 100 μg/kg ondansetron during a standardized anesthetic. Episodes of postoperative vomiting or retching were recorded. Results: Intravenous ondansetron in a dose of 50 μg/kg was more effective than placebo or a dose of 10 μg/kg in controlling the incidence and frequency of emesis in the hospital and during the first 24 postoperative hours. Increasing the dose of ondansetron to 100 μg/kg intravenously did not significantly reduce the incidence or frequency of emesis compared to 50 μg/kg intravenously. Conclusions: Intravenous ondansetron in a dose 50 μg/kg is as effective as larger doses for the prophylaxis of emesis in children undergoing surgical procedures known to be associated with an increased risk for postoperative nausea and vomiting.