Studies on the Renal Excretion of Radioactive Digitoxin in Human Subjects with Cardiac Failure

Abstract

Randomly labeled C¹⁴-digitoxin was used in a quantitative study of the renal excretion of unchanged digitoxin and its metabolites in three human subjects with cardiac insufficiency. The elimination of approximately 60 to 80 per cent of an administered dose through the kidney suggests that the major route of elimination of digitoxin in cardiac patients is through the urinary route. There is a marked initial excretion of digitoxin during the first two days after administration of the radioactive drug followed by a gradual leveling off of the excretion gradient thereafter. Minute amounts of unchanged digitoxin have been detected in the urine up to the fortieth day after administration of a single dose of the glycoside, while C¹⁴-labeled compounds were detected up to the seventy-fourth day.