Efficacy and Safety of Low-Dose versus High-Dose Postoperative Intrathecal Morphine in 62 Women Undergoing Elective Cesarean Section Delivery at Full Term.

BACKGROUND Adequate pain control is desired in women undergoing cesarean section. This study aimed to compare the efficacy and safety of low- and high-dose postoperative intrathecal morphine in 62 women undergoing elective cesarean section delivery at full term. MATERIAL AND METHODS We performed a prospective, randomized, controlled, multicenter clinical study from April to November 2022. Full-term, 22-38-year-old pregnant women who were singleton pregnancies, weighing 55-80 kg, scheduled for elective cesarean section, were enrolled. A total of 62 patients were randomly assigned into either the low-dose (60 µg morphine, N=32) or high-dose (100 µg morphine, N=30) group. Post-cesarean pain intensity was recorded at 4, 12, and 24 hours. Patients requiring additional rescue analgesics or with adverse effects were documented. RESULTS There were no differences in age, weight, height, gestational age, or operating time between the 2 groups (all P>0.05). The 2 groups also had no statistically significant differences in the resting and exercise pain intensities at 4, 12, and 24 hours after cesarean section (P>0.05). Most patients (53 patients) did not require additional analgesics, suggesting an overall successful analgesic rate of 85.5%. The low-dose group had a lower incidence of pruritus than the high-dose group (13% vs 40%, P=0.029). The 2 groups had no differences in the other adverse effects. CONCLUSIONS A single dose of intrathecal 60 µg morphine could provide adequate analgesia comparable with 100 µg morphine, with a lower incidence of pruritus, in Chinese women after cesarean delivery.