Digoxin pharmacokinetics in congestive heart failure

The steady-state pharmacokinetics of oral digoxin in eight hospitalized patients was compared upon their admission with marked right-sided congestive heart failure and later when they were compensated. Large intersubject variations in the serum digoxin concentration profiles were observed. However, over a 24-hour dosing interval, digoxin concentrations in each patient studied during heart failure were either similar or higher than those observed when the patient became compensated. There were no significant differences in digoxin half-life of elimination between the two states. In contrast, the mean ratio of the fraction of digoxin dose absorbed to its apparent volume of distribution was increased by 37 per cent (P less than 0.05) in heart failure. Contrary to the prevailing notion, we found that the oral administration of supplemental doses of digoxin only on the basis of its reduced serum concentration in patients with congestive heart failure is unwarranted.