The effects of morphine and fentanyl alone or in combination added to intrathecal bupivacaine in spinal anesthesia for cesarean section.

OBJECTIVES: This randomized double-blind controlled trial examined the effects of fentanyl and morphine, alone and in combination, as adjuncts to spinal anesthesia for elective cesarean section.

METHODS: Sixty women undergoing elective cesarean section, with spinal anesthesia using 0.5% hyperbaric bupivacaine, were randomly allocated to receive morphine 0.2 mg, fentanyl 25 µg, or fentanyl 12.5 µg plus morphine 0.1 mg, intrathecally. The start of spinal block, the time to T10 level, the highest sensorial and motor block level, time to regression of sensory block to T10, time to resolution of motor block, surgical characteristics, maternal side effects, Apgar and NACS scores, umbilical blood gas evaluations, and time to first analgesic requirement were recorded.

RESULTS: No patient experienced pain during the intraoperative period. The degree and time of sensorial and motor block were similar in both groups, and there was no difference in time to T10 level and time to reversal of motor block. The difference in time to first postoperative analgesic requirement was statistically significant. There was no difference between groups in postoperative side effects. There were no neonatal differences in Apgar and NACS scores or umbilical blood gas evaluations.

CONCLUSION: The quality of postoperative analgesia with morphine, when used alone, was found to be superior to that with fentanyl. The combination of opioids offered no advantages over morphine alone.