Effect of Combined Epidural Morphine and Midazolam on Postoperative Pain in Patients Undergoing Major Abdominal Cancer Surgery

Clin J Pain. 2022 Sep 19. doi: 10.1097/AJP.0000000000001071. Online ahead of print.

Abstract

Objective: The objective was to compare analgesic effect of combined epidural morphine-midazolam with either drug alone on postoperative pain in patients undergoing major abdominal cancer surgery.

Materials and methods: Eighty four patients were allocated in prospective randomized double-blind study to receive epidural analgesia. Patients received 5 mg morphine in morphine (Mor) group, 5 mg midazolam in midazolam (Mid) group, 5 mg morphine +5 mg midazolam in morphine- midazolam (MM) group, 0.25% bupivacaine was added to injected solution with same volume in all groups. All groups were compared with time of first analgesic request, total analgesic consumption, number of epidural doses, postoperative VAS score, and adverse events.

Results: Time of first analgesic request was [4-8] h in Mid versus [12-23] h and [14-24] h in Mor and MM groups respectively, with significant difference between Mid versus Mor (P<0.001), Mid versus MM (P<0.001), and Mor versus MM groups (P<0.031). Analgesic consumption was more in Mid than Mor and MM groups, with significant difference between Mid versus Mor (P<0.008), Mid versus MM (P<0.001), with no significant difference between Mor and MM groups (P<0.6). Number of epidural doses in Mid was [1-3] versus [1-3] and [1-2] in Mor and MM groups respectively, with significant difference between Mid versus Mor (P<0.025), Mid versus MM (P<0.004), with no significant difference between Mor and MM groups (P=1.0).

Conclusion: Addition of midazolam to epidural morphine prolonged time of first analgesic request and decreased total analgesic consumption.