Thromboembolic disorders:

Indications for: Warfarin

Venous thrombosis. Pulmonary embolism. Thromboembolic complications from atrial fibrillation and/or cardiac valve replacement. Reduce risk of death, recurrent MIs, and thromboembolic events (eg, stroke, systemic embolization) post-MI.

Adult Dosage:

Individualize. ≥18yrs: Initially 2–5mg once daily. Usual maintenance: 2–10mg once daily. Variations in CYP2C9 or VKORC1 enzymes, elderly, debilitated, Asians: use lower initial and maintenance doses. Closely monitor INR; adjust dose based on response and clinical condition. Conversion from heparin or other anticoagulants: see full labeling.

Children Dosage:

<18yrs: see full labeling.

Warfarin Contraindications:

Hemorrhagic tendencies. Blood dyscrasias. Recent CNS, ophthalmic, or traumatic surgery. Bleeding tendencies associated with certain conditions. Threatened abortion, eclampsia, and preeclampsia. Unsupervised patients with potential high levels of non-compliance. Major regional or lumbar block anesthesia. Spinal puncture and other procedures with potential uncontrollable bleeding. Malignant hypertension. Pregnancy in women without mechanical heart valves.

Boxed Warning:

Bleeding risk.

Warfarin Warnings/Precautions:

Risk of major or fatal bleeding. Monitor INR frequently. History of GI bleed. Hypertension. Cerebrovascular disease. Anemia. Malignancy. Trauma. Discontinue if tissue necrosis, calciphylaxis, systemic atheroemboli or cholesterol microemboli occurs; consider alternative therapy if needed. Heparin-induced thrombocytopenia with or without thrombosis syndrome; do not use as initial therapy. Hepatic or renal impairment; monitor INR/bleeding more frequently. Infection. Disturbances of intestinal flora. Indwelling catheter. Protein C and S deficiency. Polycythemia vera. Vasculitis. Diabetes. Diarrhea. Poor nutritional status. Steatorrhea. Vitamin K deficiency or intake. Hereditary warfarin resistance. Eye surgery. Dental procedures. Elderly; monitor more frequently. Asian. Debilitated. Anticoagulation may persist 2–5 days after discontinuation. Write ℞ using fractions rather than decimals. Pregnancy in women with mechanical heart valves. Females of reproductive potential should use effective contraception during therapy and for at least 1 month after final dose. Nursing mothers.

Warfarin Classification:

Coumarin anticoagulant.

Warfarin Interactions:

See full labeling. Potentiated by CYP2C9, 1A2 and/or 3A4 inhibitors. Antagonized by CYP2C9, 1A2 and/or 3A4 inducers. Caution with drugs that can increase risk of bleeding (eg, anticoagulants, antiplatelets, NSAIDs, SSRIs) or herbal products (eg, garlic, ginkgo biloba, co-enzyme Q10, St. John's wort, ginseng, echinacea, grapefruit juice, goldenseal). Closely monitor INR when starting or stopping any antibiotic or antifungal agent. Cholestatic hepatitis with concomitant ticlopidine.

Adverse Reactions:

Tissue or organ hemorrhage, hypersensitivity reactions, hepatic disorders, GI disorders, skin disorders, tracheal or tracheobronchial calcification, chills; skin or tissue necrosis, calciphylaxis, systemic atheroemboli and cholesterol microemboli (eg, purple toes syndrome), acute kidney injury.


Formerly known under the brand name Coumadin.

How Supplied:

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