[Proceedings: Studies on the digoxin resorption in patients with decompensated right cardiac insufficiency]

Digoxin absorption was investigated in 7 patients suffering from severe right cardiac failure. After successful treatment and disappearance of the symptoms of right cardiac failure, the study was repeated in the same patients. Tritium-labelled digoxin in a dose of 0.1 mg as a solution, and non-labelled digoxin as a 0.25 mg tablet, were given to the patients in the fasting state. Blood samples were taken at specified time intervals up to 120 h and the urine was collected during the same period. The concentrations of digoxin in plasma and urine were measured in a liquid scintillation counter. The unlabelled digoxin was estimated by radioimmunoassay. The concentrations obtained in the plasma and urine were used to compute pharmacokinetic parameters. There was no significant difference in the plasma concentration curves in severe right cardiac failure and after successful treatment, nor did the calculated pharmacokinetic parameters differ significantly. Inhibition of digoxin absorption in severe right cardiac failure therefore seems unlikely.