Steady-state kinetics of digoxin in the elderly

Area of Science:

• Pharmacology
• Geriatrics
• Nephrology

Background:

• Digoxin is a common cardiac glycoside used for heart failure and arrhythmias.
• Elderly patients often have altered renal function, impacting drug clearance.
• Optimizing digoxin therapy in the elderly requires understanding its pharmacokinetic profile.

Purpose of the Study:

• To determine the renal clearance of digoxin in elderly patients.
• To investigate the relationship between digoxin and creatinine clearance.
• To assess digoxin's pharmacokinetic parameters for safer and more effective maintenance therapy in the elderly.

Main Methods:

• Simultaneous measurement of digoxin and creatinine clearance in 28 elderly patients.
• Quantification of 24-hour urinary digoxin excretion at various doses.
• Calculation of net biliary clearance and correlation with serum digoxin levels.

Main Results:

• The mean ratio of digoxin to creatinine clearance was 1.04.
• Mean urinary excretion of digoxin was 42% of the daily dose.
• Calculated net biliary clearance averaged 18 ml/min.
• Observed and expected serum digoxin levels showed reasonable agreement.

Conclusions:

• Digoxin renal clearance in the elderly is comparable to creatinine clearance.
• Quantifying digoxin pharmacokinetics in the elderly allows for more rational and safer maintenance therapy.
• This understanding can lead to improved therapeutic outcomes for elderly patients on digoxin.