Preoperative intravenous administration of droperidol (1.25 mg) reduced postoperative nausea and vomiting after intrathecal morphine administration

BACKGROUND: Intrathecal morphine (ITM) is an excellent postoperative analgesic, but may often cause postoperative nausea and vomiting (PONV). We designed this prospective, randomized and controlled study to evaluate the antiemetic efficacy of low-dose droperidol for the treatment of PONV caused by ITM. METHODS: Two hundred female patients undergoing elective total hip arthroplasty were enrolled. They received spinal anesthesia with isobaric bupivacaine and 0.08 mg ITM, and 100 patients were randomly administered with 1.25 mg droperidol intravenously before operation. We observed the incidence of PONY and pain score until 24 hr after operation, and investigated the doses of anti-hypotensive drugs (ephedrine and phenylephrine) and fluid administered intraoperatively. RESULTS: The incidence of PONV was lower in the droperidol group within 6 hr after operation (control group 47%, droperidol group 15%), and especially lower within 2 hr (43% vs. 3%), but was not different 6 hr after operation. The pain score was very low throughout the observation period in both groups and especially within 12 hr. The respective doses of the anti-hypotensive drugs and fluid administered intraoperatively during the operation were higher in the droperidol group. Severe arrhythmia was not observed in any patient throughout the observation period. CONCLUSIONS: Single intravenous administration of 1.25 mg droperidol before operation showed prophylactic efficacy in early PONV caused by ITM. The duration of droperidol action was shorter than that of ITM. Hence we recommend that droperidol should be administered more frequently or continuously in the postoperative period.