Comparison of tocainide and prajmalium bitartrate for the treatment of ventricular arrhythmias.

The antiarrhythmic efficacy of tocainide, a new antiarrhythmic substance, has been compared with that of prajmalium bitartrate, a drug in clinical use for many years in the German speaking countries. The investigation was performed as a double-blind cross-over study in 20 patients with ventricular arrhythmias (VA) of various origin. The efficacy was assessed by serial Holter monitoring. Plasma levels were measured to study the dose-effect relationship. Applying to the criterion of a reduction of VA of more than 75% or an improvement according to the Lown grading 8 pts. under tocainide and 7 under prajmalium bitartrate were responders. Side effects were few and under tocainide only 2 pts. had to discontinue the therapy. From the present findings tocainide and prajmalium bitartrate have the same efficient antiarrhythmic effects in the majority of patients.