Materials and Methods: This randomized double-blind clinical trial controlled with placebo was conducted on 110 patients with class I and II ASA who underwent C-section with spinal anesthesia. Patients within the age range of 20-30 years were divided into 2 groups including 55 subjects. The first group received 10 mg IV metoclopramide while the second group received 10 and 0.4 mg bolus of the metoclopramide-phenylephrine combination before the spinal anesthesia and after closing the umbilical cord, respectively. Prophylactic phenylephrine was injected after the spinal anesthesia. In addition, the patients were anesthetized using bupivacaine 10 mg plus fentanyl 10 mg. Hemodynamic was monitored every 3 minutes. Further, intraoperative and postoperative complications, nausea and its intensity, cut-off point, sedation score, and epinephrine were recorded.

Results: No significant difference was found regarding demographic characteristics. (P > 0.05). The incidence and severity of nausea and vomiting were significantly lower in metoclopramide-ondansetron group compared to the metoclopramide group (P = 0.033 & P = 0.03, respectively). As regards the phenylephrine infusion, there were no significant differences in blood pressure, heart rate, and ephedrine consumption between the 2 groups. Furthermore, the incidence of other complications like shivering and pruritis was similar in both groups.

Conclusions: Generally, it was revealed that combination therapy with metoclopramide and ondansetron along with prophylaxis of the hypotension with phenylephrine can significantly reduce intra and PONV and its severity in patients undergoing C-section surgery during spinal anesthesia.