Inhibitor of zymogen synthesis: WARFARIN
- drug and disease interactions are major limitations to WARFARIN use, particularly in older patients
-
more specifically, WARFARIN tends to be underutilized due to concerns about increased bleeding risk
-
- patient education is a critical component of WARFARIN treatment
-
changes in lifestyle (esp. diet, alcohol consumption), disease and/or medication (including OTC drugs) can alter the effectiveness of WARFARIN --- in both positive and negative ways
-
-
predicting drug and disease interactions is based on an understanding of the PHARMACOKINETIC and PHARMACODYNAMIC properties of WARFARIN - PHARMACOKINETIC properties determine the concentration of a drug at its site of action; in the case of WARFARIN:
- ABSORPTION: oral
- DISTRIBUTION: plasma protein bound
-
METABOLISM and ELIMINATION: actions are terminated by CYP450 metabolism
-
PHARMACODYNAMIC effects are those that influence the ability of WARFARIN to interact with clotting factor zymogens
- PHARMACOKINETIC properties determine the concentration of a drug at its site of action; in the case of WARFARIN:
- another way of looking at it is to divide interactions into those that:
- interactions that increase its actions are the most critical to understand because of WARFARIN's low therapeutic index