Prevention of postoperative nausea and vomiting after spinal morphine for Caesarean section: comparison of cyclizine,dexamethasone and placebo

Background. Low-dose intrathecal (spinal) morphine (0.1–0.2mg) for Caesarean section delivers excellent postoperative analgesiabut is associated with significant nausea and vomiting. We comparedthe antiemetic efficacy of cyclizine, dexamethasone, and placeboin this clinical setting. Methods. Ninety-nine women undergoing elective Caesarean sectionunder spinal anaesthesia were allocated randomly, in a double-blindstudy design, to receive either cyclizine 50 mg, dexamethasone8 mg, or placebo as a single-dose infusion in saline 0.9%, 100ml on completion of surgery. Spinal anaesthesia consisted of:hyperbaric bupivacaine 0.5%, 2.0 ml; fentanyl 10 µg; andspinal morphine 0.2 mg. The primary outcome measure was theincidence of nausea. Results. The incidence of nausea was significantly less in patientsreceiving cyclizine compared with dexamethasone and placebo(33 vs 60 and 67%, respectively, P<0.05). Severity of nauseaand number of vomiting episodes were also less at 3–6h in cyclizine patients. Overall satisfaction with postoperativecare at 24 h, expressed on a 100 mm visual analogue scale, wasgreater in cyclizine 78 (28)] than either dexamethasone 58(31), P=0.03] or placebo 51 (28), P=0.008]. Conclusion. We conclude that following spinal morphine 0.2 mgand fentanyl 10 µg analgesia for Caesarean section, cyclizine50 mg i.v. reduces the incidence of nausea compared with dexamethasone8 mg i.v. or placebo. It also lessens the severity of nauseaand vomiting, and increases maternal satisfaction in the earlypostoperative period. Br J Anaesth 2003; 90: 665–70