Objective: To evaluate the postoperative analgesic efficacy of intrathecal morphine after general anesthesia for elective laparotomy in abdominal surgery.

Patients and Methods: This was a prospective, comparative, two-group study conducted over one year, from September 2, 2023, to August 31, 2024. Adult patients of both sexes undergoing laparotomy for abdominal surgery under general anesthesia were included.

Two groups were formed: one group receiving intrathecal morphine (GA+ITM) and a control group (GA).

Results: One hundred patients, 50 in the GA+ITM group and 50 in the GA group, were included. The mean age of patients in the GA+ITM group was 42.88±16.71 years and 48.34±16.65 years in the GA group. The sex ratio was 0.37. Hypertension was the most frequent comorbidity in both groups. ASA I classification represented 78% of the GA+ITM group and 52% of the GA group. The total dose of fentanyl consumed intraoperatively showed a sparing of 270 γ in the GA+ITM group. Hypotension was the most common intraoperative adverse event, with 72% in the GA+ITM group and 64% in the GA group. The VAS score was significantly lower in the GA+ITM group, demonstrating excellent analgesia with a significant reduction in postoperative analgesic consumption. Adverse effects were mainly postoperative nausea and vomiting (PONV) in the GA+ITM group (14%). Mortality was negligible.

Conclusion: Intrathecal morphine administration is an effective modality for preventing postoperative pain after abdominal surgery, but prevention of its side effects must be considered in patient management.