Related Experiment Video
Updated: Aug 23, 2026

The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation
Published on: February 28, 2012
Warfarin and other coumarin derivatives: pharmacokinetics, pharmacodynamics, and drug interactions
1University of Washington School of Pharmacy; Anticoagulation Services, University of Washington Medical Center, Seattle WA, USA. akwitt@u.washington.edu
Abstract:
Warfarin, a racemic mixture of R- and S-enantiomers, exerts its anticoagulant effect by interfering with the hepatic synthesis of vitamin K-dependent clotting factors II, VII, IX, and X and proteins C and S. Warfarin displays stereospecific pharmacokinetic and pharmacodynamic properties, and the isomers are differentially metabolized by cytochrome p450 isozymes. Among patients treated with warfarin, there is little correlation among dose, serum concentration, and therapeutic effect, necessitating individualized dosing guided by therapeutic monitoring of the prothrombin time. The pharmacokinetic and pharmacodynamic properties of warfarin as well as its narrow therapeutic index make it particularly susceptible to interactions with other prescription and nonprescription drugs, including dietary supplements. Numerous drug compounds are reported to interact with warfarin, necessitating increased prothrombin time monitoring and warfarin dosing adjustments to maintain safe and effective anticoagulation.
Related Concept Videos
Anticoagulant Drugs: Vitamin K Antagonists and Direct Oral Anticoagulants
Warfarin, a prominent vitamin K antagonist family member, exerts its effect by inhibiting the enzyme VKORC1 (vitamin K epoxide reductase complex 1). By hindering this enzyme, warfarin...
Pharmacokinetics: Drug–Food and Drug–Viral Interactions
Pharmacokinetics: Drug–Drug Interactions
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Pharmacogenetics of Drug Metabolism: Overview