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

Background. Low-dose intrathecal (spinal) morphine (0.1-0.2 mg) for Caesarean section delivers excellent postoperative analgesia but is associated with significant nausea and vomiting. We compared the antiemetic efficacy of cyclizine, dexamethasone, and placebo in this clinical setting. Methods. Ninety-nine women undergoing elective Caesarean section under spinal anaesthesia were allocated randomly, in a double-blind study design, to receive either cyclizine 50 mg, dexamethasone 8 mg, or placebo as a single-dose infusion in saline 0.9%, 100 ml on completion of surgery. Spinal anaesthesia consisted of: hyperbaric bupivacaine 0.5%, 2.0 ml; fentanyl 10 mug; and spinal morphine 0.2 mg. The primary outcome measure was the incidence of nausea. Results. The incidence of nausea was significantly less in patients receiving cyclizine compared with dexamethasone and placebo (33 vs 60 and 67%, respectively, P<0.05). Severity of nausea and number of vomiting episodes were also less at 3-6 h in cyclizine patients. Overall satisfaction with postoperative care at 24 h, expressed on a 100 mm visual analogue scale, was greater 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 mg and fentanyl 10 μg analgesia for Caesarean section, cyclizine 50 mg i.v. reduces the incidence of nausea compared with dexamethasone 8 mg i.v. or placebo. It also lessens the severity of nausea and vomiting, and increases maternal satisfaction in the early postoperative period.