Adding droperidol to morphine patient-controlled analgesia: Effect on nausea and vomiting

This prospective, double-blind, randomized, controlled trial was performed to evaluate the antiemetic effectiveness and side effects of adding droperidol to morphine delivered via a patient-controlled analgesia (PCA) device in 94 women undergoing transabdominal hysterectomy with a standardized anesthetic regimen. They were randomly allocated to receive postoperative PCA as either bolus doses of morphine 1 mg or a combination of morphine 1 mg and 0.0625 mg droperidol with a lockout interval of 5 minutes and no continuous infusion. The incidence of nausea 6-18 hours postoperatively and 18-24 hours postoperatively was significantly lower in the morphine and droperidol group than in the morphine only group and its severity 2-6 hours, 6-18 hours, and 18-24 hours postoperatively was significantly lower. The number needed to treat to prevent nausea comparing the morphine only group at 6-18 and at 18-24 hours postoperatively were 4 and 4 (95% CI 2-27 and 2-11, respectively). The amount of morphine used 6-18 hours postoperatively in the droperidol group was lower than in the morphine only group. Although the incidence of vomiting and the amount of rescue antiemetics were lower in the morphine and droperidol group, the difference was not statistically significant. Postoperative pain scores were not different between the groups. No patients were oversedated. A series of extrapyramidal reactions were observed in one patient in the morphine and droperidol group. The drug and consumable item cost was not different between the groups. We conclude that droperidol added to morphine in PCA reduces nausea. The appropriate dose of droperidol should be further investigated to reduce the incidence of vomiting.