Abstract
Anticoagulants of the cumarin-type (warfarin, phenprocoumon, and acenocoumarol) are
drugs for the long-term treatment and prevention of thromboembolic disorders. Because
of their narrow therapeutic range, many patients have bleedings of variable severity
or have recurrent thrombotic events. For this reason, the study of the pharmacokinetic
parameters of phenprocoumon (PPC), considering its influence on blood clotting factors,
is of high interest. The elimination kinetics of PPC, its interaction with phytomenadion
(vitamin K), and the pharmacokinetic behavior of the anticoagulant under steady-state
conditions have been investigated in studies with healthy volunteers and patients
taking anticoagulants. The maintenance dose and the plasma levels of PPC were correlated
with prothrombin time (PT) in 89 patients treated with PPC. Varying parameters in
each patient (e.g., elimination kinetics of PPC, activity of the cumarin-dependent
blood-clotting factors, endogenous phytomenadion stores), render it impossible to
use a different means of monitoring than that of PT determination.
Keywords:
Phenprocoumon - phytomenadion - pharmacokinetics - prothrombin time - drug interactions
