Antiarrhythmic drugs and polyneuropathy. The Collaborative Group for the Study of Polyneuropathy.

A total of 151 patients on chronic treatment with amiodarone and other antiarrhythmic drugs were subjected to standard clinical and electrophysiological investigation to assess the prevalence and specificity of polyneuropathy. Twenty two untreated patients with cardiac disorders and 246 normal subjects served as controls. Abnormal electrophysiological findings supporting the diagnosis of polyneuropathy were present in 38 subjects (25%) given antiarrhythmic drugs, with even distribution among drugs, and four untreated patients (18%). Concurrent clinical abnormalities were present in five treated patients (one each with amiodarone, propafenone, and flecainide, and two with multiple drugs). Therefore, electrophysiological abnormalities are a common, although non-specific, feature in patients taking antiarrhythmic drugs. Amiodarone users do not seem at higher risk of polyneuropathy than subjects treated with other drugs or even untreated patients with cardiac disorders.