COMBINED LOW-DOSE CLONIDINE WITH FENTANYL AS AN ADJUVANT TO SPINAL BUPIVACAINE 0.5% FOR ANAL SURGERY

Clonidine (alpha2 adrenergic agonist)has analgesic effect at spinal level mediated by postsynaptically situated alpha2 adrenoreceptors in the dorsal horn of spinal cord. Previous study demonstrated higher incidence of side effects as hypotension, sedation, motor blockade, when used clonidine intrathecally in higher doses. Sixty adults patients belonging to ASA grade I and II, scheduled for anal surgery under spinal anesthesia were randomly divided into 4 groups: clonidine group, receive 30Ug clonidine added to bupivacaine0.5%; fentanyl group, receive 50Ug fentanyl added to bupivacaine0.5%; fentanyl /clonidine group, receive15Ug clonidine combined with 25Ug fentanyl added to bupivacaine 0.5%; and, control group, received only bupivacaine0.5%.The spinal anesthesia was performed in sitting position. All patients received 2ml of the tested drugs. The patients were maintained in the sitting position for 10min. Although the sensory block level was sufficient for surgery to all patients and satisfactory anesthesia were obtained in all patients, the addition of clonidine (15Ug) to fentanyl (12,5Ug) as adjuvant to bupivacaine 0.5%, prolonged the time to first analgesic request and decreased the postoperative pain with minimal risk of hypotension and sedation. Thus we concluded that the addition of low doses clonidine to fentanyl as adjuvant to spinal bupivacaine 0.5% significantly increased the duration of spinal analgesia with clinical insignificant influences on hemodynamic parameters and level of sedation.