A double-blind, placebo-controlled pilot study examining the effectiveness of intravenous ondansetron in the prevention of postoperative nausea and emesis.

Study Objective: To compare the efficacy and safety profiles of ondansetron and a placebo when infused immediately prior to anesthesia induction for the prevention of postoperative nausea and emesis (vomiting or retching).

Design: Randomized, double-blind, placebo-controlled, parallel, multicenter pilot study.

Setting: Three U.S. ambulatory surgical facilities.

Patients: One hundred eighty ASA physical status I and II women scheduled to undergo ambulatory gynecologic surgical procedures while receiving general endotracheal anesthesia.

Interventions: Ondansetron 8 mg or a placebo (equivalent volume) was given intravenously (IV) prior to anesthesia induction to prevent postoperative nausea and vomiting.

Measurements And Main Results: For the first 24 hours following emergency from anesthesia, patients were monitored in the postanesthesia care unit by a research observer and at home via telephone contact and diary cards. More patients in the ondansetron group (62%) than in the placebo group (40%) were emesis-free over the 24-hour study period (p = 0.005). Ondansetron also was more efficacious than the placebo over the 24-hour study period when a surgery duration of more than 45 minutes was considered in the analyses. For all patients, regardless of surgery duration, there was a low degree of nausea during the course of the study. In all instances, the degree of nausea was slightly lower for ondansetron-treated patients than for placebo-treated patients; however, in no instances were the differences statistically significant. Ondansetron and placebo had similar safety profiles as established by laboratory test results, vital sign monitoring, and adverse event reporting.

Conclusion: Ondansetron, infused IV before anesthesia induction, appears to be safe and effective when used in the prevention of postoperative nausea and emesis.