Warfarin
Brand: Coumadin / Marevan / Warfilone
Anticoagulant
Vitamin K epoxide reductase inhibitor
Pharmacokinetics
| Half-life | 36 hours |
| Tmax | 1 h |
| Bioavailability | 99 % (approx) |
| Protein Binding | 99 % |
| Volume of Distribution | 0.14 L/kg (approx) |
| Clearance Route | hepatic |
| Active Metabolites | no |
| Notes | Highly protein-bound; narrow therapeutic index; strictly first-order elimination in therapeutic range. |
⚠️ Safety & Warnings
Severity: Severe
Adverse Effects:
Bleeding (GI, intracranial), skin necrosis (rare, protein C deficiency), purple toe syndrome, teratogenicity (fetal warfarin syndrome)
Contraindications:
Pregnancy (especially 1st trimester), active bleeding, severe liver disease, recent major surgery, uncontrolled hypertension
Precautions:
Requires INR monitoring; major food-drug interactions (vitamin K intake affects dose); multiple CYP2C9 interactions; caution in elderly or renal impairment