Comparison of the Effect of Oral and Intravenous Ondansetron on Decreasing Nausea and Vomiting After Cesarean Section

Background: Caesarean section is one of the most common gynecologic surgeries and nausea and vomiting after pain are the most common side effects of surgeries. Today, serotonin receptor antagonists are most widely used that are the most effective antiemetics and have less side effects compared with other drugs. Ondansetron is considered a typical serotonin antagonist. Materials and Methods: This randomized, double-blind clinical trial was done on 162 women undergoing cesarean section. Four mg intravenous ondansetron was administered to the first group and 8 mg oral ondansetron was given to the second group and the third group received placebo. Blood pressure and heart rate were measured before and immediately after performing spinal anesthesia every 5 minutes until 20 minutes. Post-operative nausea and vomiting and APGAR score were recorded after operation in recovery and 2, 4, and 6 hours after surgery. Results: There were no significant differences among the 3 groups according to age, gravidity, mean atrial pressure, and heart rate before and during surgery. Nausea and vomiting in oral and intravenous groups at recovery 2 and 4 hours after surgery were significantly less than placebo group (P<0.05), whereas there were no significant differences between oral and intravenous groups. Conclusion: It can be concluded that using oral ondansetron with the same antiemetic effect is more appropriate for women undergoing cesarean section with spinal anesthesia.