[Comparison of digitoxin bioavailability from tablets and elixir during maintenance therapy (author's transl)].

The bioavalability of digoxin tablets and solution has been studied during maintenance therapy in a cross over study. Each preparation was given over a period of at least 7 days to patients with compensated congestive heart failure. Urine concentrations and plasma levels were analysed for digitoxin. There was no significant difference between the two preparations. Determination of steady state serum concentrations and urinary excretion during maintenance therapy as an index of bioavalability are more cumbersome than a single dose study. From a pharmacokinetic point of view however, analyses of steady-state conditions are preferable to a single dose study. In addition, steady state of drug input and output resembles the usual digitalis therapy.