Table 2.

Pharmacokinetics of warfarin. Vd: volume of distribution, PO: per os (orally), INR: international normalized ratio.

	Warfarin
Type	Racemic mixture
Origin	Synthetic molecule
FDA approval	1954
Target	Vitamin K-dependent coagulation factors II, VII, IX, and X
Available administration route	PO
Absorption	Stomach and proximal small bowel
Bioavailability	80%–100%
Vd	8–10 L
Protein binding	95%–97%
Time to peak concentration (h)	1–2
Monitoring	INR test
Half-life (h)	20–60
Elimination	Major hepatic metabolism, biotransformation > 90% of inactive metabolites (CYP 2C9)
Neutralizing agent	Vitamin K