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Decreased renal clearance of digoxin in chronic congestive heart failure
Insights
Patients with chronic heart failure exhibit significantly reduced renal digoxin clearance compared to those with atrial fibrillation. This impaired clearance can increase digoxin levels, potentially leading to toxicity even without overdose.
Area of Science:
- Pharmacology
- Nephrology
- Cardiology
Background:
- Digoxin is a crucial medication for managing cardiac conditions.
- Renal function significantly impacts digoxin elimination.
- Chronic heart failure (CHF) may alter drug metabolism and excretion.
Purpose of the Study:
- To compare renal digoxin clearance in patients with CHF versus those with atrial fibrillation (AF) and preserved cardiac function.
- To investigate potential factors contributing to altered digoxin pharmacokinetics in CHF.
Main Methods:
- Comparative study involving two groups: patients with AF (n=9) and patients with CHF (n=10).
- Measurement of renal digoxin clearance, creatinine clearance, diuresis, and urinary sodium excretion.
- Analysis of steady-state serum digoxin concentrations.
Main Results:
- Digoxin clearance was significantly lower in the CHF group (48 ± 21 ml/min) compared to the AF group (71 ± 36 ml/min).
- The ratio of digoxin clearance to creatinine clearance (Cdig/Ccreat) was also significantly reduced in CHF patients (0.73 ± 0.15 vs 1.09 ± 0.27).
- Higher steady-state serum digoxin concentrations were observed in patients with CHF (1.44 ± 0.47 µg/L) compared to AF patients (0.87 ± 0.33 µg/L).
Conclusions:
- Chronic congestive heart failure is associated with reduced renal digoxin clearance.
- This diminished clearance may increase the risk of digoxin toxicity in CHF patients, independent of renal function or drug interactions.
Abstract:
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 concerning 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 X min-1, p less than 0.05), and Cdig/Ccreat was similarly reduced at 0.73 +/- 0.15 compared to 1.09 +/- 0.27 (p less than 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 micrograms X 1(-1), p less than 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.