Indian Journal of Fundamental and Applied Life Sciences ISSN: 2231-6345 (Online) An Online International Journal Available at http://www.cibtech.org/jls.htm 2012 Vol. 2 (4) October-December, pp.24-33/Singh and Shukla Research Article 24 RANDOMIZED, CONTROLLED STUDY TO COMPARE THE EFFECT OF INTRATHECAL CLONIDINE AND DEXMEDETOMIDINE ON SENSORY ANALGESIA AND MOTOR BLOCK OF HYPERBARIC BUPIVACAINE Rampal Singh and *Aparna Shukla Department of Anesthesiology Rohilkhand Medical College and Hospital Bareilly (Uttar Pradesh) India * Author for Correspondence ABSTRACT Introduction- Newer α-2 agonistic agents have opened a new chapter in the history of postoperative analgesia. Material and methods- Ninety adult patients of ASA grade I and II were divided into three groups of thirty patients each. Group A, B and C patients received inj. bupivacaine (15 mg) intrathecally with normal saline, with clonidine (50mcg) and with dexmedetomidine (5mcg) respectively. Pulse rate and noninvasive blood pressure was recorded after every 5 minutes. Degree of motor block (bromage scale), time to reach sensory block to T8 level (cold alcohol swab) ,time of regression of sensory block to S1 dermatome and time to reach Bromage 1 was assessed. Result and conclusion :.Onset time of sensory and motor block was greater in group B and C. Regression time of sensory block to S1 dermatome was significantly higher in group A vs B, group A vs C and group B vs C (210.0+32.69min , 268.93+ 62.75min and 404.43+ 114.83min for group A,B andC respectively). Regression time to reach bromage 1 was significantly high in group B and C as compared to A ( 172.11+ 29.77 min , 231.93+70.57min and 309.93+101.71min for group A, Band C respectively)[group B vs C : t=3.451; p=0.001]. Heart rate and mean arterial pressure remained at significantly lower level in Group B and Group C as compared to Group A. It can be concluded that though both clonidine and dexmedetomidine prolonged duration of sensory and motor block of bupivacaine, dexmedetomidine is better in terms of longer duration of action. Key Words: Dexmedetomidine, Clonidine , Bupivacaine and Intrathecal INTRODUCTION Intrathecal α 2 agonist clonidine or dexmedetomidine [DXM] have become very popular among surgeons and anaesthesiologists as an adjuvant to bupivacaine. Results of the previous studies show that addition of either of these two agents intrathecally significantly prolongs the duration of both sensory and motor analgesia of hyperbaric bupivacaine. Clonidine has been used extensively and studied as an adjuvant to bupivacaine in almost all the types of nerve blocks [1, 2] . The mechanism of action of dexmedetomidine differs from clonidine as it posses selective alpha 2-adrenoceptor agonistic activity especially for the 2A subtype of this receptor, which causes it to be a much more effective sedative and analgesic agent than clonidine. While clonidine has been in use as an adjuvant to bupivacaine in subarachnoid block, there are only a few studies available on human upon intrathecal uses of dexmedetomidine. Therefore we designed this study to compare the effect and side effects of addition of clonidine and dexmedetomidine to intrathecal hyperbaric bupivacaine. MATERIALS AND METHODS After approval of institutional ethical committee, prospective, randomized single blind trial was carried out in 90 normotensive adult patients of ASA grade I and II undergoing surgeries below the level of umbilicus. ASA grade III ,IV patients, patients with significant cardiovascular, renal ,hepatic dysfunction, morbidly obese patients and patients having allergy to either clonidine or bupivacaine or having contraindication to subarachnoid block were excluded from the study. Computer generated randomization was used to allocate the patients into three groups of thirty patients each. Group a patients received