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Background: The addition of clonidine to lidocaine intravenous regional anesthesia (IVRA) has been previously reported to improve postoperative analgesia in patients undergoing upper extremity surgery . Our objective was to perform a dose ranging study in order to determine the optimal dose of clonidine used with lidocaine in IVRA. Design & Setting: We performed a double-blinded randomized placebo-controlled study with 60 patients scheduled for elective endoscopic carpal tunnel release under IVRA with 50 ml lidocaine 0.5%. University-affiliated outpatient surgery center . Data collected in operating rooms, recovery room, and by telephone after discharge from surgery center . Materials & Methods: Sixty adult ASA I or II patients undergoing outpatient endoscopic carpal tunnel release under intravenous regional anesthesia. Patients were randomized into five study groups receiving different doses of clonidine in addition to 50 ml 0.5% lidocaine in their IVRA. Group A received 0 mcg/kg, group B 0.25 mcg/kg, group C 0.5 mcg/kg, group D 1.0 mcg/kg and group E 1.5 mcg/kg of clonidine. Intraoperative fentanyl, recovery room pain scores, time to first postsurgical analgesic, total number of acetaminophen/codeine tablets consumed postsurgery , incidence of sedation, hypotension and bradycardia. Results & Conclusions: There was no benefit from any dose of clonidine compared to placebo. There were no clonidine- related side effects seen within the dose range studied. In short duration minor hand surgery , the addition of clonidine to lidocaine-based intravenous regional anesthesia provides no measurable benefit. [ABSTRACT FROM AUTHOR]