Comparison of the effect of adding midazolam versus fentanyl to intrathecal levobupivacaine in patients undergoing cesarean section: double-blind, randomized clinical trial

Background: Many adjuvants are added to prolong the effects of spinal analgesia. We investigated the postoperative analgesic efficacy of the addition of midazolam or fentanyl to intrathecal levobupivacaine in women undergoing cesarean delivery. Methods: Eighty patients were randomly assigned to two groups (n = 40). Group M received 10 mg of 0.5% levobupivacaine plus 2 mg of midazolam. Group F received 10 mg of 0.5% levobupivacaine plus 25 mg of fentanyl. Assessments included motor and sensory block, APGAR score, time to first request for analgesia, postoperative pain score, total consumption of rescue analgesics, and adverse effects. Results: Sensory blockade was prolonged in Group M compared with Group F (215.58 +/- 27.94 vs. 199.43 +/- 19.77 min; p = 0.004), with no differences in other characteristics of the spinal block in intraoperative hemodynamics or APGAR score. The mean time to first request for rescue analgesia was longer in Group M (351.45 +/- 11.05 min) than in Group F (268.83 +/- 10.35 min; p = 0.000). The median total consumption of rescue analgesics in the first 24 hours postoperatively was 30 mg in Group M vs. 60 mg in Group F (p = 0.003). The median Visual Analog Scale (VAS) scores were lower in Group Ethan in Group F from the 8th to the 12th hour postoperatively, with no differences between the groups at other time points. The incidence of adverse effects was higher in Group F than in Group M. Conclusion: Intrathecal midazolam (2 mg) was superior to intrathecal fentanyl (25 mg) in increasing the duration of the sensory blockade and postoperative analgesia with lower postoperative pain scores and decreasing the incidence of adverse effects. (c) 2022 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).