title: Intrathecal orphenadrine elicits spinal block in the rat.
abstract: The purpose of this study was to estimate the local anesthetic effect of orphenadrine, an anti-muscarinic agent, in spinal anesthesia and its comparison with the local anesthetic lidocaine. After the rat was injected intrathecally, the spinal block of orphenadrine and lidocaine was constructed in a dosage-dependent fashion. The potency and duration of spinal anesthesia with orphenadrine were compared with that of lidocaine. Our data demonstrated that orphenadrine and lidocaine elicited dose-dependent spinal blockades on the motor function, sensory, and proprioception. On the 50% effective dose (ED50) basis, the ranks of potency in motor function, nociception, and proprioception were orphenadrine>lidocaine (P<0.01). At equipotent doses (ED25, ED50, ED75), the block duration elicited by orphenadrine was greater than that elicited by lidocaine (P<0.01). Orphenadrine, but not lidocaine, exhibited longer duration of nociceptive/sensory blockade than that of motor blockade at equipotent doses. Ineffective-dose orphenadrine as adjuvant did not enhance spinal anesthesia with lidocaine. The preclinical data revealed that orphenadrine with a more sensory-selective action over motor block exhibited more potent and longer spinal anesthesia when compared to lidocaine.
authors.affiliation: Department of Physical Therapy, China Medical University, Taichung, Taiwan; Department of Medical Research, Chi-Mei Medical Center, Tainan City, Taiwan.
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Chen
authors.affiliation: Department of Food Sciences and Technology, Chia Nan University of Pharmacy and Science, Jen-Te, Tainan City, Taiwan; Department of Anesthesiology, Chi-Mei Medical Center, Yong Kang, Tainan City, Taiwan.
authors.forename: Jann-Inn
authors.initials: JI
authors.lastname: Tzeng
authors.affiliation: Division of Physical Therapy, Department of Physical Medicine and Rehabilitation, Cheng Hsin General Hospital, Taipei, Taiwan.
authors.forename: Yu-Chung
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Department of Physical Therapy, National Cheng Kung University, No.1, University Road, 701 Tainan City, Taiwan. Electronic address: chhung@mail.ncku.edu.tw.
authors.forename: Ching-Hsia
authors.initials: CH
authors.lastname: Hung
authors.affiliation: Department of Medical Research, Chi-Mei Medical Center, Tainan City, Taiwan.
authors.forename: Jhi-Joung
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D000775:Anesthesia, Spinal / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D007278:Injections, Spinal; D008012:Lidocaine / Q000008:administration & dosage; D008297:Male; D018727:Muscarinic Antagonists / Q000008:administration & dosage; D059225:Nociception / Q000187:drug effects; D009966:Orphenadrine / Q000008:administration & dosage*; D011434:Proprioception / Q000187:drug effects; D011597:Psychomotor Performance / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000779:Anesthetics, Local; D018727:Muscarinic Antagonists; D008012:Lidocaine; D009966:Orphenadrine
keywords: Lidocaine; Motor function; Nociception; Orphenadrine; Proprioception; Spinal anesthesia