Comparison of the Efficacies of Three Different Intrathecal Doses of Morphine in Achieving Postcesarean Delivery Analgesia.

Purpose: The objective of this study is to compare the efficacies of 3 different intrathecal doses (80, 120, and 160 mcg) of morphine in achieving postcesarean delivery analgesia and the severity of the side effects thereof.

Design: A prospective, randomized, double-blind study.

Methods: A total of 150 pregnant women between the ages of 18 and 40, with a gestational week >36, who were planned to have elective cesarean section were included in the study. Patients were randomized into 3 groups based on the dosages of intrathecal doses of morphine (80, 120, and 160 mcg) they will receive in addition to 10 mg 0.5% hyperbaric bupivacaine and 20 mcg fentanyl. Intravenous (IV) patient-controlled analgesia (PCA) prepared with fentanyl was administered to each patient after the surgery. Postoperative 24-hour total IV PCA-fentanyl consumption was recorded. The patients were evaluated for side effects such as pain, nausea-vomiting, pruritus, sedation score, and respiratory depression after the surgery.

Findings: PCA-fentanyl consumption was significantly higher in Group 1 compared to Group 2 and 3 (P = .047). There was no significant differences between the groups in terms of nausea-vomiting scores. The pruritus scores were significantly higher in Group 3 compared to Group 1 (P = .020). The pruritus scores were significantly higher in all groups at the postoperative 8th-hour (P = .013). Respiratory depression, which would require treatment, was not observed in any patient.

Conclusions: Based on the study findings, it was concluded that 120 mcg intrathecal morphine provides adequate analgesia with minimal side effects in cesarean sections.