While spinal anaesthesia has many advantages, the limited duration of action appears to be one of its downsides. Intrathecal α 2 agonists prolong the duration of action of local anaesthetics and reduce the required dose. The intrathecal use of clonidine, a partial α 2 adrenoceptor agonist, has been shown as an effective and safe procedure (1, 2). Dexmedetomidine is an α 2 receptor agonist and its α 2 /α 1 selectivity is 8 times higher than that of clonidine. In animal models, intrathecal dexmedetomidine has been demonstrated to have an analgesic effect (3). Levobupivacaine is a long-acting local anaesthetic with a pharmacological structure similar to that of bupivacaine. Levobupivacaine has been shown to have a larger safety margin and less neurotoxic and cardiotoxic sideeffects than bupivacaine (4).In this study, we aimed to investigate the influences of dexmedetomidine added to levobupivacaine on the time of onset of spinal block and durations of sensory and motor blocks in patients undergoing transurethral endoscopic surgery by spinal anaesthesia. Materials and MethodsThe present prospective, randomised, double-blind study was approved by the Ethics committee of Erciyes University Medical Faculty, and written informed consent was obtained from the patients. The study was conducted according to the Declaration of Helsinki. Patients were aged between 50-80 years with ASA physical status I-III and were scheduled for elective transurethral endoscopic surgery under spinal anaesthesia. Using the sealed envelope method, the patients were randomly allocated into two groups: Group L (n=30) or Group LD (n=30). Patients who were taking α-adrenergic agonist or antagonist therapy, as well as patients who had labile hypertension, autoimmune disorders, a known allergy to study drugs, heart block/dysrhythmia or any contraindication to spinal anaesthesia were excluded from the study. Pharmacological premedication was not applied to patients. After arrival at the operating theatre, baseline systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) measurements, peripheral oxygen saturation (SpO 2 ) and electrocardiography monitoring were measured by an ABSTRACTBackground: Intrathecal α2 agonists prolong the duration of action of local anesthetics and reduce the required dose. Dexmedetomidine is an α2 receptor agonist and its α2/α1 selectivity is 8 times higher than that of clonidine.

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