A Comparison of the Effects of Fentanyl and Remifentanil on Nausea, Vomiting, and Pain after Cesarean Section

Background: The effects of different opioids on postoperative nausea and vomiting (PONV) and pain have not been conclusively determined. The aim of this study was to compare the effects of fentanyl, remifentanil or fentanyl plus morphine on the incidence of PONV and pain in women subjected to cesarean section under general anesthesia. Methods: The study was a randomized clinical trial recruiting 96 parturients with American Society of Anesthesiologists (ASA) physical status I and II. They scheduled for cesarean section under general anesthesia using sodium thiopental, succynylcholine, and isoflurane O2/N2O 50/50 mixture. After clamping the umbilical cord, the patients were given fentanyl (2 µg/kg/h), remifentanil (0.05 µg/kg/h), or fentanyl (2 µg/kg) pulse morphine (0.1 mg/kg) intravenously. Visual analog scale for pain and nausea, frequency of PONV, meperidine and metoclopramide consumption were evaluated at recovery, and 4, 8, 12 and 24 hours after the surgery. Results: There was no significant difference between the three groups in terms of frequency of nausea, vomiting, and mean nausea and pain scores at any time points. None of the patients required the administration of metoclopramide. However, the mean VAS for pain in remifentanil-treated group was insignificantly more than that in fentanyl- or fentanyl plus morphine-treated group at recovery or 4 hours after the surgery. The mean mepridine consumption in remifentanil-treated group was significantly (P=0.001) more than that in fentanyl- or fentanyl plus morphine-treated group in 24 hours after the surgery respectively. There was no significant difference in hemodynamic parameters of the three groups in all measurements after the surgery. Conclusion: The findings of this study showed that early postoperative analgesia was better with fentanyl, and postoperative meperidine consumption was significantly less with fentanyl than with remifentanil or combined fentayl and morphine.