Dose-independent pharmacokinetics of digoxin in humans.
Nine healthy male volunteers received single 0.5, 1.0, and 1.5 mg. doses of intravenous digoxin in a randomized three-way crossover study. Multiple venous blood samples were drawn during 35 hours after each dose, and all urine was collected for 6 consecutive days. Concentrations of digoxin in serum and urine were determined by radioimmunoassay. Over-all mean values for kinetic variables were: distribution half-life, 0.35 hours; elimination half-life, 27.9 hours; volume of distribution, 5.46 liters/Kg; total clearance, 2.51 ml./min./Kg. The mean projected cumulative urinary excretion of digoxin was 70.1% of the dose; mean renal clearance of digoxin was 1.71 ml./min./Kg., not significantly different from creatinine clearance (1.50 ml./min./Kg.). None of the identifiable pharmacokinetic variables was significantly influenced by dose, suggesting that digoxin disposition is dose-independent in healthy individuals.
D000328:Adult; D002986:Clinical Trials as Topic; D004077:Digoxin / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006207:Half-Life; D006801:Humans; D007263:Infusions, Parenteral; D007700:Kinetics; D008297:Male; D014556:Urine / Q000032:analysis
D004077:Digoxin