The cutaneous analgesic effect of class I antiarrhythmic drugs.
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.
Tzeng
Jann-Inn
JI
Department of Medical Research, Chi-Mei Medical Center, Tainan, Taiwan.
Cheng
Kuang-I
KI
Huang
Kuo-Lun
KL
Chen
Yu-Wen
YW
Chu
Koung-Shing
KS
Chu
Chin-Chen
CC
Wang
Jhi-Joung
JJ
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
D000700:Analgesics; D000779:Anesthetics, Local; D000889:Anti-Arrhythmia Agents; D026941:Sodium Channel Blockers; D008801:Mexiletine; D008012:Lidocaine; D011802:Quinidine; D005424:Flecainide; D002045:Bupivacaine