Prevention of postoperative nausea and vomiting after intrathecal morphine for Cesarean section: a randomized comparison of dexamethasone, droperidol, and a combination.

BACKGROUND: Intrathecal morphine provides good analgesia after cesarean delivery but the side effects include nausea and vomiting. Low-dose droperidol (0.625 mg) combined with dexamethasone 4 mg is postulated to have an additive antiemetic effect with less side effects. We therefore compared single doses of dexamethasone and droperidol alone with a low-dose combination of the two, to prevent spinal morphine-induced nausea and vomiting after cesarean section.

METHODS: In a double-blind study, 120 women undergoing elective cesarean section under spinal anesthesia (using 0.5% bupivacaine 10 mg and morphine 0.2 mg) were allocated randomly to receive dexamethasone 8 mg, droperidol 1.25 mg, dexamethasone 4 mg and droperidol 0.625 mg, or placebo, before the end of surgery. The incidences of nausea and vomiting, sedative score, pain score, and side effects were recorded.

RESULTS: The incidence of nausea and vomiting within 6 h postoperatively was lower and incidence of no nausea and vomiting for 24 h postoperatively was significantly higher for the combination group compared to the placebo group and the dexamethasone only group. Sedation scores within 3 h postoperatively and incidence of restlessness for the combination group were significantly lower than in the droperidol only group.

CONCLUSION: An additive antiemetic effect and no significant side effects were shown for the combination of dexamethasone 4 mg and droperidol 0.625 mg. This combination was more effective than either dexamethasone 8 mg or droperidol 1.25 mg alone in preventing nausea and vomiting after spinal anesthesia using 0.5% bupivacaine and morphine 0.2 mg.