title: The cutaneous analgesic effect of class I antiarrhythmic drugs.
abstract: BACKGROUND
  Local anesthetics, when applied to nerves, produce reversible loss of sensation by blocking Na+ channels. Because all Class I antiarrhythmic drugs are Na+ channel blockers, theoretically, they may have local anesthetic effects. In this study, we sought to define the cutaneous local anesthetic actions of three Class I antiarrhythmic drugs.
  
  
  METHODS
  Using a subcutaneous infiltration model in rats, the potencies and durations of action of quinidine (Class IA), mexiletine (IB), and flecainide (IC) were determined and compared with the actions of lidocaine and bupivacaine. Saline injection was used as control.
  
  
  RESULTS
  Three Class I antiarrhythmic drugs produced a dose-related cutaneous analgesia with ranking of potencies of bupivacaine > flecainide > quinidine > mexiletine > lidocaine (P < 0.05 for the differences among drugs). On an equipotent basis, the ranking of durations of action was flecainide > quinidine and bupivacaine > mexiletine and lidocaine (P < 0.05 for the differences among drugs).
  
  
  CONCLUSIONS
  Three Class I antiarrhythmic drugs, quinidine (IA), mexiletine (IB), and flecainide (IC) have a local anesthetic effect on cutaneous analgesia.
authors: Department of Medical Research, Chi-Mei Medical Center, Tainan, Taiwan.
authors: Jann-Inn
authors: JI
authors: Tzeng
authors: Kuang-I
authors: KI
authors: Cheng
authors: Kuo-Lun
authors: KL
authors: Huang
authors: Yu-Wen
authors: YW
authors: Chen
authors: Koung-Shing
authors: KS
authors: Chu
authors: Chin-Chen
authors: CC
authors: Chu
authors: Jhi-Joung
authors: JJ
authors: Wang
mesh_terms: D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002045:Bupivacaine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005424:Flecainide / Q000494:pharmacology; D007279:Injections, Subcutaneous; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D008801:Mexiletine / Q000494:pharmacology; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects*; D011802:Quinidine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000187:drug effects*; D012867:Skin / Q000294:innervation*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000700:Analgesics; D000779:Anesthetics, Local; D000889:Anti-Arrhythmia Agents; D026941:Sodium Channel Blockers; D008801:Mexiletine; D008012:Lidocaine; D011802:Quinidine; D005424:Flecainide; D002045:Bupivacaine