Postmortem tissue and plasma concentrations of digoxin in newborns and infants.

Postmortem tissue and plasma concentrations of digoxin were studied in 13 premature newborns, 6 mature newborns, and 5 older infants (age 1 to 14 months). The pertinent results of our study are as follows: The tissue digoxin concentrations tend to be higher in premature and mature newborns than in infants. This difference is statisitcally significant with respect to the concentration in myocardium and skeletal muscle. The renal digoxin concentration of premature newborns is significantly lower than that of mature newborns, the tissue concentrations in the other organs examined being essentially equal. In all age groups examined, skeletal muscle contains the greatest portion of digoxin, followed by the liver. The relation of myocardial to plasma digoxin concentration shows no significant difference between the various age groups. Within the groups, the variation is relatively large.