Warfarin

Category: pharmacological

Aliases: Coumadin, Jantoven

Pharmacological Mechanism

Inhibits vitamin K epoxide reductase (VKOR) → depletes reduced vitamin K → prevents γ-carboxylation of factors II, VII, IX, X + proteins C/S. Narrow therapeutic index + massive interaction list + dietary K variability → DOACs (apixaban, rivaroxaban) now preferred for non-valvular indications.

Half-Life (t½)

PO: 40h

Dosing Guidelines

• PO: Typical 4.67mg (Range: 2 - 10 mg)

Target Organ Systems

• immune-hematologic

Interactions

• Vitamin K1
• Vitamin K2 MK-7
• Vitamin E
• St. John's Wort
• Cholestyramine
• Acetaminophen
• Apixaban
• Dabigatran
• Edoxaban
• Rivaroxaban
• Tamoxifen
• CoQ10
• Menaquinone-4 (MK-4)