Pharmacodynamics of 3H-digoxin in infants.

Abstract

The absorption, tissue concentration, and urinary and fecal excretion of 3H-digoxin was studied in 20 infants with serious congenital cardiac malformations and, except for minor differences, the results were in the same range as those reported for adults. The published recommendations of higher dosage requirements in infants for maximum therapeutic effectiveness and the suggested lower dosage for the neonatal period to reduce the danger of toxicity can therefore not be explained by differences in absorption, tissue fixation, and excretion of the glycoside by the neonate and infant when compared with the adult. A major difference is that infants excrete primarily unchanged digoxin, whereas adults excrete both unaltered digoxin and metabolites.