Randomised double-blind comparison of ondansetron and droperidol to prevent postoperative nausea and vomiting associated with patient-controlled analgesia

In a randomised, double-blind trial, we compared the use of ondansetron and droperidol for the prevention of nausea and vomiting after total abdominal hysterectomy, during patient-controlled analgesia with morphine. One hundred and forty-two patients were randomly allocated to one of two groups. All patients received a standardised general anaesthetic and postoperative analgesic regimen. One group received ondansetron 4 mg at induction of anaesthesia, and ondansetron 0.13 mg with each 1-mg bolus dose of morphine. The other group received droperidol 0.5 mg at induction and droperidol 0.05 mg per 1-mg bolus dose of morphine. Results were available for 137 patients. During the first 24 h after surgery, prophylaxis was as successful in 26 of 66 patients given ondansetron (39%) compared with 36 of 71 patients given droperidol (51%). This difference was not statistically significant (Chi-squared = 1.766, p = 0.18). We conclude that in the regimens studied, ondansetron is not more effective than droperidol at preventing postoperative nausea and vomiting.