title: Lidocaine for prolonged and intensified spinal anesthesia by coadministration of propranolol in the rat.
abstract: Although the coadministration of lidocaine with propranolol interferes with the metabolic profile (pharmacokinetics), its pharmacodynamics is still unclear. In this report, we investigate whether propranolol can potentiate the effect of lidocaine. Rats received spinal anesthesia with lidocaine co-injected with propranolol. After intrathecal injections of drugs in rats, three neurobehavioral examinations (motor function, proprioception, and nociception) were performed. We showed that lidocaine and propranolol elicited a spinal blockade in motor function, proprioception, and nociception. Propranolol at the dose of 0.82 μmol/kg produced no spinal anesthesia. Co-administration of lidocaine [50% effective dose (ED(50)) or ED(95)] and propranolol (0.82 μmol/kg) produced greater spinal anesthesia than lidocaine (ED(50) or ED(95)), respectively. These preclinical findings demonstrated that propranolol and lidocaine displayed spinal anesthesia. When combined with propranolol, lidocaine elicited a supra-additive effect of spinal anesthesia.
authors.affiliation: Department of Physical Therapy, China Medical University, Taichung, Taiwan.
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Chen
authors.forename: Chin-Chen
authors.initials: CC
authors.lastname: Chu
authors.forename: Yu-Chung
authors.initials: YC
authors.lastname: Chen
authors.forename: Ching-Hsia
authors.initials: CH
authors.lastname: Hung
authors.forename: Yung-Tsung
authors.initials: YT
authors.lastname: Li
authors.forename: Jhi-Joung
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D000775:Anesthesia, Spinal; D000818:Animals; D019540:Area Under Curve; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004357:Drug Synergism; D007278:Injections, Spinal / Q000379:methods; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D059225:Nociception / Q000187:drug effects*; D011433:Propranolol / Q000008:administration & dosage*; D011434:Proprioception / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004338:Drug Combinations; D008012:Lidocaine; D011433:Propranolol