Sotalol versus class I and II antiarrhythmic agents.

In two separate, double-blind, multicenter antiarrhythmic studies, sotalol was compared with propranolol or quinidine using placebo for baseline and/or washout periods. The comparison with quinidine was a crossover study. To be enrolled in these studies, patients were required to have a premature ventricular contraction (PVC) rate of at least 30/hr on a baseline 24-hour ambulatory ECG. At doses calculated to produce equivalent degrees of beta blockade, sotalol was more effective than propranolol in reducing the frequency of PVCs, and the two drugs produced similar reductions in ventricular tachycardia (VT) events. The side effects for sotalol and propranolol were mainly due to beta blockade, and the incidence of side effects with the two drugs was similar. Sotalol was comparable with quinidine in reducing PVCs and VT events. The side effects on sotalol were primarily related to beta-adrenergic blockade, while those on quinidine were predominantly gastrointestinal or neurologic in nature.