Digitalis glycosides like digoxin and digitoxin have distinct pharmacokinetic profiles, with digoxin relying on renal clearance and digitoxin utilizing non-renal elimination mechanisms.
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,
Tarabanis et al. (Mon,) conducted a review in Heart Failure. Digitalis glycosides (digoxin and digitoxin) was evaluated. Digitalis glycosides like digoxin and digitoxin have distinct pharmacokinetic profiles, with digoxin relying on renal clearance and digitoxin utilizing non-renal elimination mechanisms.