Revisiting Digitalis in Heart Failure: Lessons From DIGIT-HF and Beyond

Digitalis glycosides are among the oldest therapies employed in cardiovascular medicine. 1hey are naturally occurring compounds from Digitalis plant species, characterized by a sugar moiety, steroid nucleus, and terminal lactone ring.They inhibit the Na/K-ATPase, increasing intracellular sodium and secondarily calcium and producing a weakly positive inotropic effect.In parallel, they augment vagal tone at the sinoatrial and atrioventricular nodes and promote baroreceptor function.Clinically relevant preparations include digoxin and digitoxin, differing by a single hydroxyl group on the steroid ring.This structural distinction translates into clinically significant differences in pharmacokinetic properties.Digoxin undergoes primary renal clearance, with a half-life of ~36-48 hours in patients with normal renal function, versus up to 4-6 days in end-stage renal disease.Even small reductions in renal function markedly prolong digoxin's half-life and increase toxicity risk, contributing to a narrow therapeutic index.As a p-glycoprotein substrate, its serum levels are also susceptible to inhibitors such as amiodarone, quinidine, and verapamil, which enhance intestinal absorption while reducing renal clearance.By contrast, digitoxin's half-life is longer (~7 days) and elimination occurs through non-renal (i.e., enterohepatic) mechanisms,