Differential pharmacokinetics of digoxin in elderly patients

Digoxin remains one of the most commonly prescribed of all cardiac medicati ons. The main indications for digoxin usage include atrial fibrillation and heart failure; both these conditions are more prevalent in older patients. Given the aging population and the increasing incidence of heart failure w e would expect prescribing of digoxin to remain as frequent or to even incr ease in older patients. Older patients are also more likely to develop toxi city and diagnosis of digoxin toxicity can be difficult in this group. Nume rous components contribute to the development of toxicity in older patients , ranging from aging-related changes in renal function or body mass to poly pharmacy and possible interactions with digoxin. It is therefore important to understand how the pharmacokinetics of digoxin may be altered in the old er population. Application of basic pharmacological principles may be helpf ul in anticipating these problems. This review describes the pharmacokineti cs of digoxin, the changes in pharmacokinetics with increasing age and how concomitant disease states or drug interactions may affect the pharmacokine tics of digoxin. Greater knowledge about the causes and prevention of digox in toxicity should further reduce the morbidity and mortality arising from digoxin toxicity, especially in the elderly population.