Comparison of ondansetron versus placebo to prevent postoperative nausea and vomiting in women undergoing ambulatory gynecologic surgery.

BACKGROUND

Postoperative nausea and emesis, especially in ambulatory surgical patients, remains a troublesome problem. This study was performed to compare the incidence of nausea and emesis during the 24-h postoperative period in ondansetron-treated patients versus placebo-treated patients.

METHODS

Using a randomized prospective double-blind study design, women between the ages of 18 and 70 yr undergoing gynecologic surgical procedures with general opioid anesthesia on an outpatient basis were enrolled. Ondansetron or placebo was administered prior to induction of anesthesia. Patients were stratified according to history of nausea and emesis during previous exposure to general anesthesia and randomized to dose received.

RESULTS

Data from the 544 women showed that all doses of intravenous ondansetron tested (1, 4, and 8 mg) were significantly more effective (62%, 76%, and 77%, respectively) than placebo (46%) in reducing the incidence of emesis following surgery until 24 h after recovery room entry. All these doses were more effective than placebo in patients with no prior history of emesis following surgery and the 4- and 8-mg doses were more effective than placebo in patients with a prior history of emesis following surgery. All doses of ondansetron tested were generally well tolerated with adverse events, clinical laboratory tests, and recovery room vital signs similar to those of placebo. Serum aspartate transaminase (AST) was increased in five patients (1 mg, 2 patients; 4 mg, 1 patient; 8 mg, 2 patients). In the three patients in whom subsequent analysis were performed, the serum AST had decreased to preoperative levels.

CONCLUSIONS

Ondansetron given intravenously to prevent postoperative nausea and emesis was highly effective in the 4- and 8-mg doses in women having ambulatory gynecologic surgery.