ABSTRACT
Background: Clonidine, the α2 – adrenergic agonist, has a variety of different action including the ability to potentiate the effect of local anaesthetic without any significant undesirable effects. The intrathecal use of different doses of clonidine when co-administered with hyperbaric bupivacaine provides prolongation of pain free period than hyperbaric bupivacaine alone. Objectives: Our present study was targeted to find out the optimum intrathecal dose of clonidine as an adjunct to hyperbaric bupivacaine.Methods: Patients with ASA physical status I & II scheduled for elective infra umbilical surgery under spinal anaesthesia were randomly divided into four equal groups (n = 30) by a computerized randomization chart. Groups BC15, BC30, and BC45 received mixture of 10 mg hyperbaric bupivacaine plus clonidine in the doses of 15, 30, and 45 μg respectively intrathecally and the control group (Group B) received 0.5% hyperbaric bupivacaine 10 mg and normal saline as placebo. All analysis was two tailed and P value < 0.05 was considered statistically significant. Data analyzed with the help SPSS software version 16.0 for Windows, SPSS Inc. Chicago. Results: It was observed that intrathecal clonidine to hyperbaric bupivacaine dose dependently prolongs both sensory blockade of spinal anesthesia and time to request for first supplemental analgesia in post operative period. Conclusion: Because of the absence of significant adverse effects, we conclude that, within the tested dose range, 30 μg of clonidine is the preferred dose, when prolongation of spinal anesthesia is desired.