Nalbuphine versus Midazolam as an Adjuvant to Intrathecal Bupivacaine for Postoperative Analgesia in Patients Undergoing Cesarean Section

Background and Purpose: Adding adjuvants to intrathecal hyperbaric bupivacaine provides long analgesic duration with less adverse effects. The aim of this study was to compare intrathecal nalbuphine versus midazolam in patients undergoing cesarean section. Clinical Trial ID: NCT03918187. Patients and Methods: This was a prospective randomized controlled study conducted on 90 females undergoing cesarean section under spinal anesthesia who were randomly allocated to three equal groups of 30 patients each: group C received hyperbaric bupivacaine 12.5 mg plus 0.5 mL saline, group N received hyperbaric bupivacaine 12.5 mg plus 1 mg nalbuphine, group M received hyperbaric bupivacaine 12.5 mg plus 2.5 mg midazolam. The onset and duration of sensory and motor block, effective analgesic time, analgesic requirements, adverse effects, sedation, and Apgar scores were recorded. Results: There was significant rapid onset of sensory and motor block (1.95 +/-.44 and 3.50 +/- 0.43 min) with slower regression of sensory block and time to bromage I (211.6 +/- 13.2 and 219.8 +/- 20.2 min) in group N compared to groups M, C (p < 0.001), with statistically significant rapid onset and long duration of both blocks in group M compared to C (p<0.001). The effective analgesic time was significantly prolonged in group N (263.7 +/- 16.3) compared to groups M and C (224.2 +/- 18.6, 185.5 +/- 17.45), respectively, (p<0.001) and prolonged in group M compared to C (p<0.001), with increase in analgesic requirement in group C compared to groups N and M (p<0.001) and no significant difference between groups N and M. There was higher sedation score in groups N, M (1.78 +/- 0.63, 2.75 +/- 0.54), respectively, compared to group C (0.61 +/- 0.12) (p<0.001) with lower Apgar score in group M (6.9 +/- 0.73) at one minute than in groups N, C (7.1 +/- 0.91, 7.7 +/- 0.84) (p<0.001). There was no significant difference between groups regarding the adverse effects. Conclusion: Adding 1 mg nalbuphine to 12.5 mg hyperbaric bupivacaine provided more effective postoperative analgesia than adding 2.5 mg midazolam, with less non-significant adverse effects in midazolam group in patients undergoing elective cesarean section.