A comparison of droperidol and cyclizine in the prevention of postoperative nausea and vomiting associated with patient-controlled analgesia.

Fifty ASA 1 or 2 patients scheduled to undergo major gynaecological surgery were allocated randomly to one of two groups. All patients received a standard anaesthetic regimen. Patients in group 1 received droperidol 1.25 mg given intravenously 20 min prior to the end of surgery and a patient-controlled analgesia infusion containing morphine 1 mg.ml-1 and droperidol 0.05 mg.ml-1. Patients in group 2 received cyclizine 50 mg by slow intravenous injection 20 min prior to the end of surgery and a patient-controlled analgesia infusion containing morphine 1 mg.ml-1 and cyclizine 2 mg.ml-1. Fifteen of 25 patients (60%) in group 1 and 18 (72%) of 25 in group 2 suffered no nausea or vomiting postoperatively. Two patients (8%) in group 1 and three (12%) in group 2 suffered severe postoperative nausea or vomiting. We conclude that cyclizine is as effective as droperidol in the prevention of postoperative nausea and vomiting when included in a patient-controlled analgesia infusion using morphine.