Enhancement of axillary brachial plexus block anesthesia by coadministration of neostigmine

Abstract Background and Objectives . The acetylcholinesterase inhibitor neostigmine has shown peripherally mediated analgesic action in recent preclinical and clinical studies. The present study investigates the effectiveness of adding neostigmine to a local anesthetic, mepivacaine, in patients receiving axillary brachial plexus block for upper extremity surgery. Methods . In a double-blind, randomized study 34 patients were assigned to the treatment group: Neostigmine (NM) (500 μg) + mepivacaine (M) (500 mg) (NM, n = 17) as drugs for the plexus block, or to control group: mepivacaine (500 mg) + saline (0.9%, 1 mL) (M, n = 17). Results . The onset and duration of sensory and motor block was similar in both groups. Patients receiving NM had significantly lower pain ratings [visual analogue scores (VAS): 14.7 ± 9.9 vs 32.4 ± 23.5; P Conclusions . Peripherally administered neostigmine improves postoperative analgesia in axillary brachial plexus block.