The Renal Excretion of Digitoxin in the Normal Subject after Single and Continuous Administration of the Drug

By employing the embryonic duck heart method to assay digitoxin quantitatively in extracts of human urine, it was found that, contrary to previous opinion, a large percentage of ingested or in-injected digitoxin is excreted via the kidney in a physiologically active state. Approximately 40 per cent of a digitalizing dose (1.2 mg.) is excreted over a period of 12 to 24 days. The average rate of renal excretion in theoretically digitalized normal young individuals was found to vary from 30 to 50 &mgr;g. of digitoxin per day, while those showing signs or symptoms of overdosage excreted significantly greater amounts of digitoxin.