Efficacy of repeat intravenous dosing of ondansetron in controlling postoperative nausea and vomiting: A randomized, double-blind, placebo-controlledmulticenter trial

Study Objectives: To compare repeat intravenous (IV) dosing of ondansetron 4 mg with placebo for the treatment of postoperative nausea and vomiting (P ONV) in patients for whom prophylactic, preoperative ondansetron 4 mg IV wa s inadequate. Design: Randomized, double-blind, placebo-controlled study. Setting: Ten outpatient surgical centers in the United States. Patients: 2,199 male and female ASA physical status I, II, and III patients greater than or equal to 12 years old scheduled to undergo outpatient surg ical procedures and receive nitrous oxide-based general anesthesia. Interventions: Ondansetron 4 mg IV was administered to all patients before induction of general anesthesia. Patients who experienced PONV or requested antiemetic therapy within 2 hours after discontinuation of inhaled anesthe sia were randomized (1:1) to either a repeat IV ondansetron 4 mg dose or pl acebo. Measurements and Main Results: Of th 2,199 patients prophylactically treate d with ondansetron 4 mg before anesthesia induction. 1,771 (80.5%) did not experience PONV or request antiemetic therapy during the 2 hours following discontinuation of anesthesia. Of the 428 patients who experienced PONV or requested antiemetic therapy during the same period, and wee randomized to additional treatment (214 randomized to ondansetron, 214 randomized to plac ebo), the incidence of complete response (no emesis, no rescue medication, no study withdrawal) was similar for both ondansetron-randomized and placeb o-randomized groups for the 2-hour (34% and 43%, respectively, p = 0.074) a nd 24-hour (28% and 32%, respectively, p = 0.342) postrandomization study p eriods. Repeat ondansetron dosing was not more effective than placebo in co ntrolling either postoperative emesis or the severity/duration of postopera tive nausea. The administration of an additional dose of ondansetron 4 mg p ostoperatively did not result in an increased incidence of adverse effects. Conclusions: In patients for whom preoperative prophylaxis with ondansetron 4 mg IV is not successful, a repeat dose of ondansetron 4 mg IV in the pos tanesthesia care unit does not appear to offer additional control of PONV. (C) 1999 by Elsevier Science Inc.