Intrathecal Midazolam for Postoperative Analgesia in Adults

Introduction: Midazolam produces an analgesic action through the benzodiazepine/γ-aminobutyric acid (GABA)A receptor complex in the spinal cord. We conducted this study to evaluate postoperative analgesic effects and associated complications of intrathecal midazolam in patients undergoing perineal surgery. Material and methods: 30 subjects belonging to ASA grade I and II scheduled to undergo elective perineal surgery under spinal anaesthesia were randomly allocated to either Group A1 ml of 0.5% heavy bupivacaine+saline or Group B1 ml of 0.5% heavy bupivacaine+preservative free midazolam. The duration of postoperative analgesia, postoperative visual analogue scores for pain, and perioperative side effects were noted. Results: The basic demographic characteristics were similar between the two groups. The mean duration of surgery was 22.33 ± 14.96 in group A, and it was 16.8 ± 12.55 in group B. The mean time to first pain medication was 4.93 ± 3.32 hours in group A, and it was 8.63 ± 6.17 in group B. The mean VAS at first pain medication was 40.00 ± 00 mm, and it was 40.00 ± 00 mm in group B. the mean difference in the postoperative analgesia between group was statistically significant (P value <0.02). Hemodynamic parameters did not differ between the groups. The complications included urinary retention among 5 (33.33%) in group A and 6 (40.00%) in group B. Conclusion: The addition of preservative-free midazolam to bupivacaine intrathecally resulted in prolonged postoperative analgesia without any significant side effects.