Background & Aims: Nausea and vomiting during spinal anesthesia for elective cesarean delivery is a common finding and may occur in up to 80% of patients. The aim of the present study was to compare efficacy of using intravenous midazolam alone, ondansetron, and midazolam in combination with ondansetron for prevention of nausea and vomiting during and after cesarean delivery in parturient that underwent spinal anesthesia.

Materials & Methods: In a double-blind study, 126 women undergoing elective caesarean section under spinal anesthesia (using 0.5% bupivacaine 12.5 mg) were allocated randomly to receive midazolam 2 mg (n=42), ondansetron 4 mg (n=42) or midazolam and ondansetron (n=42) after the clamping umbilical cord. The frequency of nausea and vomiting during and after surgery in recovery room were recorded.

Results: The frequency of intraoperative nausea and vomiting was lower in the O (28.6, 7.1%) and MO (26.2, 16.7%) groups compared with M (50, 31%) group (P=0.04, P=0.006). The frequency of nausea and vomiting after surgery in recovery room was lower in the O (4.8, 19 %) and MO (11.9, 7.1%) groups compared with M(38.1, 23,8 %) group (P=0.01, P=0.03). Metoclopramide consumption was lower in O and MO groups compared with M group (P=0.02). There was no difference in mean arterial pressure and pulse rate between three groups during the surgery at times measured.

Conclusion: A bolus dose of midazolam (2 mg) was not effective than ondansetron (4mg) and ondansetron plus midazolam (O 4 and M 2 mg) for the prevention of nausea and vomiting in parturient patients undergoing cesarean section with spinal anesthesia during and after surgery in  recovery room; however, further studies are needed.