Effects of Intramuscular Dexmedetomidine Versus Clonidine on the Duration of Subarachnoid Block and Analgesia for Lower Limb Orthopedic Surgeries

ABSTRACT

Background: Alpha-2adrenergic agonists, when used simultaneously as systemic adjuvants to local anesthetics show synergisticaction and improve the quality of spinal anesthesia and prolong the post-operative analgesia. We aimed to study the effects ofintramuscular dexmedetomidine versus clonidine on the duration of bupivacaine sub-arachnoid block, post-operative analgesia,and sedation in patients undergoing lower limb orthopedic surgeries.Materials and Methods: The study design was a prospective, randomized, and double-blind study. Eighty adult consentedpatients of ASA I or II, scheduled for orthopedic lower limb surgeries under spinal block were randomized to two groups of40 patients per group. Group D received IM dexmedetomidine 1 μgkg−1, Group C received IM clonidine 2 μgkg−1, and 30 minbefore the bupivacaine subarachnoid block. The time of onset of sensory and motor block, the time required for completesensory and motor recovery, time of the first request of rescue analgesia, and sedation levels were compared between thegroups. Collected data were analyzed using the student “t” test, Chi-square test/Fisher exact test, and P < 0.05 was consideredstatistically significant.Results: The mean onset time of sensory and motor block was reduced, the mean time required for complete sensory recoverywas increased and the time of the first request of rescue analgesia was prolonged in the dexmedetomidine group comparedto clonidine group with a significant P < 0.05. Ramsay sedation score was higher in the dexmedetomidine group compared toclonidine group (P = 0.003)Conclusion: Premedication with a single dose of intramuscular dexmedetomidine before bupivacaine spinal anesthesia actsas an effective adjuvant and potentiates the quality of block and prolongs post-operative analgesia more than intramuscularclonidine.