Warfarin Sodium (5 brand names, 2 dosage forms, 2 routes)
Available dosage forms: TABLET, INJECTABLE.
Routes of administration: ORAL, INJECTION.
Brand Names
- ATHROMBIN
- COUMADIN
- JANTOVEN
- PANWARFIN
- WARFARIN SODIUM
Related Health Topics
Boxed Warning
Warfarin sodium can cause major or fatal bleeding [see Warnings and Precautions ( 5.1)] . Perform regular monitoring of INR in all treated patients [see Dosage and Administration ( 2.1)] . Drugs, dietary changes, and other factors affect INR levels achieved with warfarin sodium therapy [see Drug Interactions ( 7)] . Instruct patients about prevention measures to minimize risk of bleeding and to report signs and symptoms of bleeding [see Patient Counseling Information ( 17)] .
Indications and Usage
Warfarin sodium tablets are indicated for: Prophylaxis and treatment of venous thrombosis and its extension, pulmonary embolism (PE). Prophylaxis and treatment of thromboembolic complications associated with atrial fibrillation (AF) and/or cardiac valve replacement. Reduction in the risk of death, recurrent myocardial infarction (MI), and thromboembolic events such as stroke or systemic embolization after myocardial infarction. Limitations of Use Warfarin sodium tablets have no direct effect on an established thrombus, nor does it reverse ischemic tissue damage. Once a thrombus has occurred, however, the goals of anticoagulant treatment are to prevent further extension of the formed clot and to prevent secondary thromboembolic complications that may result in serious and possibly fatal sequelae.
Contraindications
Warfarin sodium is contraindicated in: Pregnancy Warfarin sodium is contraindicated in women who are pregnant except in pregnant women with mechanical heart valves, who are at high risk of thromboembolism [see Warnings and Precautions ( 5.7) and Use in Specific Populations ( 8.1)] . Warfarin sodium can cause fetal harm when administered to a pregnant woman. Warfarin sodium exposure during pregnancy causes a recognized pattern of major congenital malformations (warfarin embryopathy and fetotoxicity), fatal fetal hemorrhage, and an increased risk of spontaneous abortion and fetal mortality. If warfarin sodium is used during pregnancy or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to a fetus [see Use in Specific Populations ( 8.1)] . Warfarin sodium is contraindicated in patients with: Hemorrhagic tendencies or blood dyscrasias Recent or contemplated surgery of the central nervous system or eye, or traumatic surgery resulting in large open surfaces [see Warnings and Precautions ( 5.8)] Bleeding tendencies associated with: − Active ulceration or overt bleeding of the gastrointestinal, genitourinary, or respiratory tract − Central nervous system hemorrhage − Cerebral aneurysms, dissecting aorta − Pericarditis and pericardial effusions − Bacterial endocarditis Threatened abortion, eclampsia, and preeclampsia Unsupervised patients with conditions associated with potential high level of non-compliance Spinal puncture and other diagnostic or therapeutic procedures with potential for uncontrollable bleeding Hypersensitivity to warfarin or to any other components of this product (e.g., anaphylaxis) [see Adverse Reactions ( 6)] Major regional or lumbar block anesthesia Malignant hypertension
Adverse Reactions
The following serious adverse reactions to warfarin sodium are discussed in greater detail in other sections of the labeling: Hemorrhage [see Boxed Warning, Warnings and Precautions (5.1), and Overdosage ( 10)] Tissue Necrosis [see Warnings and Precautions ( 5.2)] Calciphylaxis [see Warnings and Precautions ( 5.3)] Acute Kidney Injury [see Warnings and Precautions ( 5.4)] Systemic Atheroemboli and Cholesterol Microemboli [see Warnings and Precautions ( 5.5)] Limb Ischemia, Necrosis, and Gangrene in Patients with HIT and HITTS [see Warnings and Precautions ( 5.6)] Other Clinical Settings with Increased Risks [see Warnings and Precautions ( 5.8)] Other adverse reactions to warfarin sodium include: Immune system disorders: hypersensitivity/allergic reactions (including urticaria and anaphylactic reactions) Vascular disorders: vasculitis Hepatobiliary disorders: hepatitis, elevated liver enzymes. Cholestatic hepatitis has been associated with concomitant administration of warfarin sodium and ticlopidine. Gastrointestinal disorders: nausea, vomiting, diarrhea, taste perversion, abdominal pain, flatulence, bloating Skin disorders: rash, dermatitis (including bullous eruptions), pruritus, alopecia Respiratory disorders: tracheal or tracheobronchial calcification General disorders: chills
Mechanism of Action
Warfarin acts by inhibiting the synthesis of vitamin K-dependent clotting factors, which include Factors II, VII, IX, and X, and the anticoagulant proteins C and S. Vitamin K is an essential cofactor for the post ribosomal synthesis of the vitamin K-dependent clotting factors. Vitamin K promotes the biosynthesis of γ-carboxyglutamic acid residues in the proteins that are essential for biological activity. Warfarin is thought to interfere with clotting factor synthesis by inhibition of the C1 subunit of vitamin K epoxide reductase (VKORC1) enzyme complex, thereby reducing the regeneration of vitamin K 1epoxide [see Clinical Pharmacology ( 12.5)] .