A Comparative study of Intrathecal Clonidine and Preservative-Free Midazolam as Adjuvants to Hyperbaric Bupivacaine in Urological Surgeries

Abstract

Background: Spinal anaesthesia using hyperbaric bupivacaine is widely practiced for urological surgeries; however, its limited duration of postoperative analgesia necessitates the use of intrathecal adjuvants. Clonidine is commonly used but is associated with hemodynamic instability. Preservative-free midazolam has emerged as a potential alternative with a more stable cardiovascular profile. This study aimed to compare intrathecal clonidine and midazolam as adjuvants to hyperbaric bupivacaine in urological surgeries.Methods: This double-blinded, prospective randomized controlled study was conducted on 60 male patients (ASA I-II), aged 18-60 years, undergoing elective urethroplasty under spinal anaesthesia. Patients were randomly allocated into two groups: Group BC received 0.5% hyperbaric bupivacaine (3.5 ml) with clonidine 1 µg/kg, and Group BM received 0.5% hyperbaric bupivacaine (3.5 ml) with preservative-free midazolam 2 mg. Sensory and motor block characteristics, hemodynamic parameters, sedation scores, respiratory parameters, duration of effective analgesia, VAS scores, and adverse effects were assessed.Results: Demographic parameters were comparable between groups. Sensory block onset and duration did not differ significantly. Motor block onset and time to peak motor block were significantly faster in the clonidine group (P < 0.01), while total duration of motor block was comparable. The duration of effective postoperative analgesia was significantly longer in the midazolam group (562.77±44.25 min vs 346.53±39.47 min; P < 0.001), with comparable VAS scores at first rescue analgesic. Clonidine was associated with significantly higher incidence of hypotension and bradycardia, as well as higher sedation scores. Respiratory parameters and oxygen saturation remained clinically stable in both groups.Conclusion: Intrathecal midazolam provides longer and superior postoperative analgesia with better hemodynamic stability and minimal sedation compared to clonidine, making it a safer and effective alternative as an intrathecal adjuvant to hyperbaric bupivacaine in urological surgeries.