What it's used for
Warfarin sodium is used for the prevention and treatment of venous thrombosis and pulmonary embolism, management of thromboembolic complications from atrial fibrillation or heart valve replacement, and reducing the risk of death, recurrent heart attack, and stroke after myocardial infarction.
Source: U.S. FDA-approved prescribing information (openFDA).
Typical dosing
Dosing must be individualized for each patient and adjusted based on INR response, with daily INR determinations upon initiation until stable in the therapeutic range.
Dosing shown here is the general FDA-labeled range. Your prescribing clinician determines the exact dose, form, and schedule for you — this is not a substitute for medical advice.
Boxed warning / key safety info
Warfarin sodium can cause major or fatal bleeding, requiring regular INR monitoring in all treated patients.
Common side effects
Serious adverse reactions include hemorrhage, tissue necrosis, calciphylaxis, acute kidney injury, and systemic atheroembolism.
Covered strengths on the Tab $0 list
Covered at $0 with an active Tab membership when filled at a participating pharmacy nationwide or through mail order. A licensed clinician must prescribe the medication.
Related medications
Other heart, blood pressure & cholesterol medications covered at $0 with an active Tab membership.
Warfarin cost without insurance
Cash prices for Warfarin without insurance vary widely by pharmacy, strength and quantity — the same prescription can cost very different amounts at two pharmacies in the same town. That is the problem a membership solves.
Warfarin is on Tab's covered $0 generic list. With an active Tab membership, every covered strength is $0 — not a percentage off, not a coupon that changes month to month — at participating pharmacies nationwide or through mail order. You do not need insurance, and Tab works whether or not you have a health plan.
Tab is a membership, not insurance. Covered medications require a prescription from a licensed clinician.
Warfarin dosage and administration
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 International Normalized Ratio (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.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Your prescribing clinician decides the exact dose, form and schedule for you — this is not medical advice.
Warfarin side effects
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.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. This is not a complete list. Report side effects to your clinician, and seek care for anything severe or unexpected.
Warfarin drug interactions
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 General Information 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).
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Tell your clinician and pharmacist about every medication, supplement and over-the-counter product you take.
Who should not take warfarin
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 )] .
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Whether this medication is appropriate for you is a clinical decision made by your prescribing clinician.
Common questions
Is warfarin covered at $0 with Tab?
Yes. Warfarin is on Tab's covered $0 generic list — every covered strength is $0 with an active membership, at participating pharmacies nationwide or by mail order.
Do I need insurance to get warfarin through Tab?
No. Tab is a membership, not insurance. Covered medications are $0 with an active membership whether or not you have a health plan.
How do I get a warfarin prescription with Tab?
Book a video visit with a licensed Tab clinician (unlimited visits are included with membership). If it's clinically appropriate, they send the prescription to your chosen participating pharmacy or by mail order.
How much does warfarin cost without insurance?
Without insurance, retail cash prices for warfarin vary by pharmacy, strength and quantity. Warfarin is on Tab's covered $0 generic list, so every covered strength is $0 with an active Tab membership at participating pharmacies nationwide or by mail order.
What is the cheapest way to get warfarin?
For medications on Tab's covered list, a Tab membership is the cheapest route: covered strengths of warfarin are $0 with an active membership, and unlimited video visits with a licensed clinician are included, so the visit that produces the prescription is covered too.
What is the usual dose of warfarin?
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. (FDA-approved label, retrieved 2026-09-15. Your clinician sets your dose.)
What are the side effects of warfarin?
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. (FDA-approved label, retrieved 2026-09-15.)
What interacts with warfarin?
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. (FDA-approved label, retrieved 2026-09-15. Tell your clinician about every medication and supplement you take.)
Warfarin is $0 on the covered list
Members pay $0 for covered generics at participating pharmacies nationwide or by mail order — plus unlimited virtual primary care, urgent care and dermatology visits. No insurance needed.
Solo $49/mo · Family $119/mo for up to 4 people · Family+ $149/mo for up to 8
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