Pharmacokinetics of digoxin in low-birth-weight infants.

Digoxin pharmacokinetics were studied in 13 low-birth-weight infants requiring digoxin therapy. Their weights ranged from 820 to 2,710 g (mean = 1,440 g) and gestational ages ranged from 26 to 38 weeks (mean = 30.9 weeks). The distribution and elimination of digoxin can be described by an open two-compartment model. Poor correlation between volume of distribution Vd beta 95.7 +/- 1.0 liters/kg) and gestational age (GA) or weight (Wt) was observed. Digoxin half-life (47 +/- 21 h) was inversely related to GA and Wt (r = 0.69 and 0.66, respectively), but total body digoxin clearance (29.8 +/- 14.7 ml/min/1.73 m2) was found to be highly dependent on these two variables (r = 0.87 and 0.88, respectively). According to the results of this study and our previous investigation, digitalizing and maintenance dosages of digoxin were recommended.