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/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.