Fig. 1
Pharmacokinetic/pharmacodynamic model of warfarin and vitamin K2. In this model, Cp 1 and Cp 3 represent the plasma concentration of warfarin and vitamin K2, respectively; Vd 1 and Vd 3 represent the distribution volume; and k 10 and k 30 represent the first-order elimination rate constant for each drug. The zero-order synthesis and first-order degradation rate constant for clotting factors are shown as k s and k d , respectively, and IC 50, E max and EC 50 represent 50 % inhibitory concentration of warfarin, maximum effect of vitamin K2 and 50 % effective concentration of vitamin K2, respectively