PHARMACOKINETICS OF DIGOXIN-SPECIFIC FAB - EFFECTS OF DECREASED RENAL-FUNCTION AND AGE

Aims To study the influence of age and renal function on digoxin-speci fic Fab (DS-Fab) pharmacokinetics. Methods Sixteen patients (35-91 yea rs) with creatinine clearance ranging from 10.6 to 122.1 ml min(-1) wh o had been admitted to hospital with severe digoxin or digitoxin self- poisoning were treated with DS-Fab (80 to 800 mg). Plasma DS-Fab conce ntrations were determined by radioimmunoassay. Results The mean (+/- s .d.) distribution and elimination half-lives, apparent volume of distr ibution and total body clearance were 1.1 +/- 0.4 h, 20.2 +/- 7.3 h, 1 3.1 +/- 5.81, and 17.6 +/- 10.8 ml min(-1) respectively. Interindividu al variability of DS-Fab total body clearance was linked linearly with the decrease in creatinine clearance or with the increase in age and DS-Fab distribution volume was not dependent on creatinine clearance o r age. Conclusions The data suggest that DS-Fab should be given to eld erly and renal-impaired patients at doses similar to those given to yo unger or normal renal function patients.