Dexmedetomidine Versus Clonidine as Additives for Spinal Anesthesia: A Comparative Study

Background: Postoperative pain management is vital to improve patient care. Successful postoperative pain relief is currently achieved only through NSAIDs and narcotics. Objectives: We compared dexmedetomidine and clonidine as additives to hyperbaric levobupivicaine 0.5% for the sub-arachnoid block (spinal anesthesia) concerning the onset time, duration of the block, hemodynamic changes, level of sedation intraoperatively and postoperatively and time taken for the first postoperative analgesic request and frequency. Methods: This prospective, double-blind study enrolled 60 patients who underwent lower abdominal surgeries and were eligible for a sub-arachnoid block. They were allocated randomly to one of the two groups. Group D received intrathecal dexmedetomidine 5 µg and 0.5% hyperbaric levobupivicaine 15 mg. Group C received intrathecal clonidine 50 µg and 0.5% hyperbaric levobupivicaine 15 mg. Results: Patients who received dexmedetomidine had a longer duration of the block (2-segment regression: 135 ± 15 min vs. 130 ± 20 min, S1 segment regression: 305 ± 50.4 min vs. 290 ± 47.2 min, Bromage 0: 285 ± 60 min vs. 280 ± 45 min), delayed first rescue analgesia request (700 ± 160 min vs. 506 ± 112 min), reduced frequency of rescue analgesics (1 vs. 2), and desired level of sedation (1.3 ± 0.46 vs. 0.4 ± 0.01) when compared to those receiving clonidine. There were insignificant differences between the groups in intraoperative hemodynamic parameters, such as minimal bradycardia and minimal hypotension. Though dexmedetomidine had an early onset, there was no statistically significant difference compared to clonidine. Conclusions: Comparing dexmedetomidine and clonidine as additives in the sub-arachnoid block, the group who received dexmedetomidine had similar onset, prolonged duration of blockade, delayed first rescue analgesia demand, reduced frequency of analgesics, and desired sedation with similar minimal hemodynamic changes such as bradycardia and hypotension.