Decreased renal clearance of digoxin in chronic congestive heart failure

Summary Renal digoxin clearance was compared in patients suffering from atrial fibrillation with well preserved cardiac function (n=9; salt intake ±170 mmol daily) and patients with chronic congestive heart failure (n=10; salt intake 50 mmol daily and maintenance treatment with diuretics). There was no difference between the groups concering digoxin dosage, creatinine clearance, diuresis or sodium excretion in the urine. Digoxin clearance in chronic heart failure proved to be significantly lower than in atrial fibrillation (48±21 vs 71±36 ml·min^–1, p<0.05), and Cdig/Ccreat was similarly reduced at 0.73±0.15 compared to 1.09±0.27 (p<0.005). Steady state serum digoxin concentration was significantly higher in patients with congestive heart failure (1.44±0.47 vs 0.87±0.33 µg·l^–1, p<0.01). Chronic congestive heart failure is a state with reduced digoxin clearance by the kidney, which could lead to digoxin intoxication not explicable by overdose, reduced renal function or the effect of interacting drugs.