Warfarin is a vitamin k antagonist sold in the U.S. under 2 brand and generic names, for atrial fibrillation, postoperative complications and pulmonary embolism. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
From the FDA label for Coumadin (application NDA009218). Other warfarin products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Individualize dosing regimen for each patient, and adjust based on INR response. ( 2.1 , 2.2 ) • Knowledge of genotype can inform initial dose selection. ( 2.3 ) • Monitoring: Obtain daily INR determinations upon initiation until stable in the therapeutic range. Obtain subsequent INR determinations every 1 to 4 weeks. ( 2.4 ) • Review conversion instructions from other anticoagulants. ( 2.8 ) 2.1 Individualized Dosing The dosage and administration of warfarin sodium tablets must be individualized for each patient according to the patient’s INR response to the drug. Adjust the dose based on the patient’s INR and the condition being treated. Consult the latest evidence-based clinical practice guidelines regarding the duration and intensity of anticoagulation for the indicated conditions. 2.2 Recommended Target INR Ranges and Durations for Individual Indications An INR of greater than 4 appears to provide no additional therapeutic benefit in most patients and is associated with a higher risk of bleeding. Venous Thromboembolism (including deep venous thrombosis [DVT] and PE) Adjust the warfarin dose to maintain a target INR of 2.5 (INR range, 2 to 3) for all treatment durations. The duration of treatment is based on the indication as follows: • For patients with a DVT or PE secondary to a transient (reversible) risk factor, treatment with warfarin for…
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 ) ] • Necrosis of skin and other tissues [ see Warnings and Precautions ( 5.2 ) ] • Systemic atheroemboli and cholesterol microemboli [ see Warnings and Precautions ( 5.3 ) ] 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 Most common adverse reactions to warfarin sodium are fatal and nonfatal hemorrhage from any tissue or organ. ( 6 )To report SUSPECTED ADVERSE REACTIONS, contact TEVA USA, PHARMACOVIGILANCE at 1-866-832-8537 or [email protected]; or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
Vitamin K–rich foods
You don't have to avoid these foods — the key is keeping your intake steady week to week rather than suddenly eating a lot more or less. Tell your clinician before making big diet changes.
Warfarin — MedlinePlus (U.S. National Library of Medicine) ↗Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Typical price | |
|---|---|---|---|---|---|---|---|
| 1 | 72/100 | Prescription | Tablet | Generic | $3 | View → | |
| 2 |
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
| Imprint | Strength | Colour | Shape | Maker |
|---|---|---|---|---|
| 765;4;AN | 4 mg | blue | oval | — |
| 766;5;AN | 5 mg | orange | oval | — |
| TV;2;1713 | 2 mg | purple | oval | — |
| 762;2;AN | 2 mg | purple | oval | — |
| TV;3;1715 | 3 mg | brown | oval | — |
A combination is a different drug — different dosing, different warnings. It is listed here so you can find it, not so you can substitute it.
The elimination half-life of warfarin is about 40 hours (the label's effective half-life; range 20 to 60 hours). Half-life varies widely between people (20 to 60 hours), partly due to CYP2C9 genetic differences, and warfarin is a mix of R- and S-warfarin that clear at different rates (R: 37 to 89 hours; S: 21 to 43 hours); the label also notes a terminal half-life of about 1 week after a single dose.
Warfarin Sodium Tablets, USP (DailyMed) ↗Half-life is how long the body takes to clear half a dose. It is not the same as how long a drug test can detect it, and it varies with age, kidney and liver function.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
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 ( 5.5 ) 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 Warnings and Precautions ( 5.6 ) and 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 ( 5.7 ) ] • 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 •…
Drugs may interact with warfarin sodium through pharmacodynamic or pharmacokinetic mechanisms. Pharmacodynamic mechanisms for drug interactions with warfarin sodium are synergism (impaired hemostasis, reduced clotting factor synthesis), competitive antagonism (vitamin K), and alteration of the physiologic control loop for vitamin K metabolism (hereditary resistance). Pharmacokinetic mechanisms for drug interactions with warfarin sodium are mainly enzyme induction, enzyme inhibition, and reduced plasma protein binding. It is important to note that some drugs may interact by more than one mechanism. More frequent INR monitoring should be performed when starting or stopping other drugs, including botanicals, or when changing dosages of other drugs, including drugs intended for short-term use (e.g., antibiotics, antifungals, corticosteroids) [ see Boxed Warning ]. Consult the labeling of all concurrently used drugs to obtain further information about interactions with warfarin sodium or adverse reactions pertaining to bleeding. • Concomitant use of drugs that increase bleeding risk, antibiotics, antifungals, botanical (herbal) products, and inhibitors and inducers of CYP2C9, 1A2, or 3A4 ( 7 ). • Consult labeling of all concurrently used drugs for complete information about interactions with warfarin sodium or increased risks for bleeding. ( 7 ) 7.1 CYP450 Interactions CYP450…
| 72/100 |
| Prescription |
| Tablet |
| Generic |
| $3 |
| View → |