[Example of dose finding in practice. Pharmacology of an antiarrhythmic agent (author's transl)].

Results of the pharmacological investigation of a new antiarrhythmic drug are presented. In the isolated guinea pig ileum the substance of the procainamide-quinidine type reveals strong activity in prolonging the relative refractory period. The safety index as to antiarrhythmic and negative-inotropic properties in relatively high. In the aconitine arrhythmia of the rat the substance is effective after i.v. or oral administration. Furthermore, in these experiments it shows a long-lasting action with these two modes of application. From experimental data in the conscious and anesthetized dog the oral efficacy can also be derived. An oral dose of the new substance for the first application in humans is proposed which refers to its pharmacological activity compared with procainamide and to the human dose of this latter substance.