Antiarrhythmic drug-induced side effects: a prospective survey of 300 patients

The purpose of this study was to define the characteristics and the frequency of antiarrhythmic drug-induced side effects. All patients referred for cardiological consultation and treated with antiarrhythmic drugs between April 1992 and October 1993 were prospectively investigated. 300 patients were included in the study: 41 (13.6 per cent) had drug-induced side effects, nine of which were serious: 5 proarrhythmic effects, 1 pulmonary fibrosis, 1 peripheral neuropathy, and 2 acute cardiac failure. Side effects led to discontinuation of treatment in 26 cases (7.6 per cent). Statistical analysis showed that side effects occurred more commonly with disopyramide (46.1 per cent, P < 0.01) or propafenone (41.7 per cent, P < 0.05) and less frequently with sotalol (2 per cent, P < 0.01) than with the other drugs (flecainide 20 per cent; amiodarone 16.4 per cent; cibenzoline 4.8 per cent; hydroquinidine 4.3 per cent). Side effects were more common on bitherapy (39 per cent) than on monotherapy (13 per cent) in general and in the amiodarone-treated group in particular. In conclusion, side effects of antiarrhythmic drugs involved 1/6 patients overall and led to discontinuation of treatment in 1/14. The frequency of proarrhythmias (1.1 per cent) was lower than previously reported, suggesting that recently published clinical trials have modified the prescription habits.