title: Rimantadine and 2-adamantanamine elicit local anesthesia to cutaneous nociceptive stimuli in a rat model.
abstract: The aim of this study was to investigate infiltrative cutaneous anesthesia of 2-adamantanamine and rimantadine. After subcutaneous injections of drugs in rats, the blockade of cutaneous trunci muscle reflex by 2-adamantanamine and rimantadine was evaluated. Lidocaine, a common local anesthetic, was used as control. We showed that rimantadine and 2-adamantanamine as well as the local anesthetic lidocaine produced infiltrative anesthesia of skin in a dose-dependent fashion. Saline (vehicle) group displayed no cutaneous anesthesia. The relative potency of these drugs was rimantadine [23.8 (21.1-26.8)] = lidocaine [26.4 (22.7-30.6)] > 2-adamantanamine [64.6 (55.0-75.9)] (P < 0.01). On an equianesthetic basis [25% effective dose (ED25 ), ED50 , and ED75 ], rimantadine and 2-adamantanamine had longer duration of action than lidocaine (P < 0.05). Neither local injection of saline nor intraperitoneal administration of a large dose of drugs elicited cutaneous anesthesia (data not shown). These data demonstrated for the first time that rimantadine had a similar potent and longer duration of skin infiltrative anesthesia than did lidocaine, whereas 2-adamantanamine had a less potency but longer duration of cutaneous anesthesia than did lidocaine.
authors.affiliation: Institute & Department of Physical Therapy, National Cheng Kung University, No.1 Ta-Hsueh Road, Tainan, 701, Taiwan.
authors.forename: Ching-Hsia
authors.initials: CH
authors.lastname: Hung
authors.forename: Chin-Chen
authors.initials: CC
authors.lastname: Chu
authors.forename: Yu-Chung
authors.initials: YC
authors.lastname: Chen
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Chen
authors.forename: Jhi-Joung
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D000547:Amantadine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D000772:Anesthesia, Local / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D007279:Injections, Subcutaneous; D008297:Male; D015394:Molecular Structure; D010147:Pain Measurement; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000187:drug effects; D012299:Rimantadine / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D012867:Skin / Q000187:drug effects* / Q000294:innervation
chemical_list: D000779:Anesthetics, Local; D012299:Rimantadine; C070094:2-aminoadamantane; D000547:Amantadine