Comparative Analgesic Efficacy of Intrathecal Fentanyl versus Intrathecal Midazolam as Adjuvants to Hyperbaric Bupivacaine for Elective Caesarean Section: A Randomized Double-Blinded Clinical Trial

Background: Intrathecal adjuvants are commonly used with hyperbaric bupivacaine to enhance spinal anesthesia for caesarean section. Both fentanyl and midazolam have been shown to improve analgesic quality, but comparative evidence remains inconsistent.

Aim: To compare the analgesic efficacy of intrathecal fentanyl and intrathecal midazolam as adjuvants to hyperbaric bupivacaine in elective caesarean section.

Methods: Sixty ASA I–II parturients undergoing elective caesarean section under spinal anesthesia were randomly allocated into two groups (n = 30 each). Group A received 0.5% hyperbaric bupivacaine (1.8 mL) with fentanyl 25 µg, while Group B received 0.5% hyperbaric bupivacaine (1.8 mL) with midazolam 1 mg. Onset and duration of analgesia, postoperative analgesic consumption, hemodynamic variables, sedation score, neonatal APGAR score, and adverse effects were compared.

Results: Both groups showed comparable onset and duration of analgesia and postoperative analgesic consumption (P > 0.05). Early postoperative pain scores were significantly lower in the fentanyl group at 90 minutes (P = 0.002) and 2 hours (P = 0.050). The incidence of hypotension was significantly higher in the midazolam group compared with the fentanyl group (63.3% vs 33.3%, P = 0.038), while heart rate, sedation scores, APGAR scores, and other adverse effects were comparable between groups.

Conclusion: Both intrathecal fentanyl and midazolam are effective adjuvants to hyperbaric bupivacaine in caesarean section. Fentanyl provides superior early postoperative analgesia, whereas intrathecal midazolam serves as an effective non-opioid alternative, although careful monitoring for early intraoperative hypotension is advisable