Effects of gallopamil, a Ca2+ channel blocker in models of ventricular arrhythmia in dogs.

The antiarrhythmic effects of gallopamil on adrenaline-, digitalis- and two-stage coronary ligation-induced arrhythmias and on adrenaline-induced triggered arrhythmia were investigated. Gallopamil suppressed adrenaline-induced and adrenaline-induced triggered arrhythmias, and these antiarrhythmic effects of gallopamil were similar to those of verapamil. Gallopamil also showed some antiarrhythmic effect on the 48-h coronary ligation-induced arrhythmia. The plasma concentration of gallopamil which decreased the arrhythmic ratio for adrenaline-induced arrhythmia by 50% (IC50) was 32 ng/ml. These results indicate that gallopamil may be a clinically useful antiarrhythmic drug.