Digitalis Pharmacology and Therapeutics: Recent Advances

Abstract

The fundamental therapeutic action of digitalis is stimulation of ventricular contractile state. The expression of this increased contractility is dependent on the integrity of cardiocirculatory status when the glycoside is administered. Thus, by interplay between direct and indirect cardiac and vascular effects, variable and even opposite changes in cardiac output, peripheral circulatory dynamics, and myocardial oxygen consumption can occur. Apparently, the fundamental positive inotropic property of digitalis now rests on an influx of calcium intracellulary, produced by the drug's action on the cardiac cell membrane. In contrast, transmembrane fluxes of sodium and potassium underlie the electrical properties of the glycosides. Future research should clarify the nature of the digitalis receptor and further define the subcellular contractile and toxic mechanisms of the agent.