title: Digoxin elimination in a functionally anephric patient after digoxin-specific Fab fragment therapy.
abstract: The elimination of total digoxin after digoxin-specific Fab fragment therapy in a patient in end-stage renal disease is described. Two-component, nonlinear exponential regression of the patient's total digoxin concentration data revealed biphasic elimination: a fast phase with a half-life of 43 h and a slow phase with a half-life of 330 h. Serum total digoxin concentration decreased 20% 12 h after the initiation of Fab fragment therapy. The mean serum concentrations of total digoxin and apparent total digoxin as measured by fluorescence polarization immunoassay during a 520-h period after the initiation of therapy were 18.42 and 14.77 ng/ml, respectively (n = 15). The correlation between the two measurements was good (r = 0.987). The time course of free digoxin concentration obtained after ultrafiltration at 2, 20, or 37 degrees C is also described. The free digoxin concentrations (n = 10) at these temperatures averaged over a 282-h period were 0.35, 0.53, and 0.82 ng/ml, respectively (p less than 0.001, 2 degrees C vs. 37 degrees C).
authors.affiliation: Department of Pathology, College of Medicine, University of Iowa, Iowa City 52242.
authors.forename: N F
authors.initials: NF
authors.lastname: Nuwayhid
authors.forename: G F
authors.initials: GF
authors.lastname: Johnson
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000188:drug therapy; D004077:Digoxin / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000627:therapeutic use*; D007676:Kidney Failure, Chronic / Q000378:metabolism*; D012044:Regression Analysis; D006435:Renal Dialysis; D014462:Ultrafiltration
chemical_list: D007140:Immunoglobulin Fab Fragments; D004077:Digoxin