Prolongation of post-operative spinal analgesia: A randomized prospective comparison of two doses of oral clonidine

Abstract

Background and Aims: Efforts to prolong analgesia with various intrathecal and oral adjuvants have been tried with varying success. The present study was aimed to explore and to compare the potential beneficial effects of prolongation of spinal analgesia with two different doses of oral clonidine. Materials and Methods: A randomized double-blind study was carried out among 60 (American Society of Anesthesiologists)-I and II patients with aged range from 25 to 65 years undergoing lower abdominal surgery. They were divided randomly into three groups of 20 each. Group 1 patients were administered placebo whereas Group 2 and 3 received oral clonidine tablets (0.15 and 0.30 mg respectively) 1-h prior to surgery. Subarachnoid block was administered as per standard protocol. Time to onset of analgesia at T-10, time to achieve maximum sensory level, dermatomal regression and time to rescue analgesia were observed. Side-effects such as hypotension, bradycardia, nausea and vomiting were noted. Statistical analysis was performed using ANOVA with post-hoc Students unpaired t-test and Chi-square test and value of P < 0.05 was considered to be significant. Results: The demographic profile and initial block characteristics were comparable among the three groups (P > 0.05). Two segment regression was 78.3 ± 10.44 min, 150.2 ± 23.07 min and 149.3 ± 18.33 min in Groups 1-3 respectively. Time to rescue analgesia was significantly prolonged in Groups 2 and 3 compared with Group 1 (P < 0.05). Incidence of hypotension was higher in Group 2 (P < 0.05). Conclusion: Optimal dose of oral clonidine that produces clinically useful prolongation of spinal anesthesia using bupivacaine appears to be 0.15 mg when compared with 0.3 mg when overall efficacy is being compared.