Pharmacokinetics and Metabolism of Digitoxin in the Human

Abstract

The present knowledge of pharmacokinetics and metabolism of digitoxin in man, derived from single dose (Caldwell et al., 1971;Doherty, 1968; Kramer et al., 1970; Lahrtz et al., 1969; Okita et al., 1953,1955; Vöhringer and Rietbrock, 1974; Weissler et al., 1966) as well as from multiple dose studies (Jelliffe, 1967; Lukas, 1971,1973; Peters et al., 1975; Solomon et al., 1971; Storstein, 1974; Wirth et al., 1976) using different methods, can be characterized as follows:

• 1. The elimination of digitoxin with a half-life of 6–8 days in plasma and urine is very slow.

• 2. The metabolism of digitoxin in man is assumed to occur with a cleavage of digitoxose side chains, with a β-hydroxylation of digitoxin to digoxin, and with a formation of polar Compounds. However, there is controversy in the literature as to exactly how far digitoxin is quantitatively metabolized. There-fore, in this paper new data on digitoxin kinetics are presented during maintenance therapy.