A Comparative Study of the Effect of Clonidine versus Fentanyl with Hyperbaric Bupivacaine on Spinal Block Characteristics

Abstract Background: Spinal anaesthesia is most widely used techniques for lower abdominal, orthopaedic, urological surgeries. Major limitation of spinal block with local anaesthetics is lack of prolonged postoperative analgesia. Addition of intrathecal adjuvants like clonidine and fentanyl improves quality and duration of block. The aim of this study was to compare the efficacy of intrathecal clonidine (1 µg/kg) and fentanyl (25 µg) as adjuvants to 0.5% 3ml hyperbaric bupivacaine on spinal block characteristics. Methodology: A prospective randomized comparative study was conducted on 100 ASA I - II patients undergoing surgeries under spinal anaesthesia. Two groups (n=50 each) were formed, Group C received clonidine 1 µg/kg with 3 ml of 0.5% hyperbaric bupivacaine and Group F received fentanyl 25 µg with 3 ml of 0.5% hyperbaric bupivacaine intrathecally. Hemodynamic stability, sensory and motor block characteristics, duration of analgesia, VAS pain scores and side effects were observed. Results: The groups were comparable with respect to demographic variables and intraoperative parameters. Clonidine group showed significantly prolonged duration of analgesia (409.04±9.84 min vs 240.16±8.86 min, p<0.001), higher sedation scores and lower VAS scores at 6th and 12th hour compared to fentanyl group. Incidence of side effects was minimal and comparable between both groups. Conclusion: Intrathecal clonidine as adjuvant to hyperbaric bupivacaine significantly prolongs sensory and motor block, enhances postoperative analgesia and provides better patient comfort compared to fentanyl, with slightly higher sedation scores. Similar findings were reported in previous studies.1,2 This is consistent with studies by Singh et al. and Tilkar et al.2,3