# Warfarin

Source: https://onco.cc/drugs/warfarin/  
OnCo record `warfarin` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Warfarin is an older blood-thinning tablet that needs regular blood tests. For a clot in someone with cancer, guidelines now prefer heparin injections or the newer tablets, but warfarin still has a place, for example with severe kidney failure.

## Summary

The warfarin label covers prophylaxis and treatment of venous thrombosis and pulmonary embolism, thromboembolism with atrial fibrillation or valve replacement, and risk reduction after myocardial infarction. ITAC 2022 prefers LMWHs over vitamin K antagonists for treating VTE in cancer when creatinine clearance is at least 30 mL/min (1A); with severe renal failure (creatinine clearance below 30 mL/min) it suggests unfractionated heparin followed by early vitamin K antagonists, or LMWH adjusted to anti-Xa levels (guidance, in the absence of data). The Coumadin NDA was approved on 8 June 1954.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-11-11
- Also known as: warfarin sodium; vitamin K antagonist
- Tags: supportive; generic; supportive-care-gaps-2026-11
- Brand: Coumadin
- Modality: Vitamin K antagonist (oral anticoagulant)
- Mechanism: A vitamin K antagonist: reduces the liver's production of active vitamin K-dependent clotting factors; dosing is monitored by the INR.
- Approvals: US 1954: Prophylaxis and treatment of venous thrombosis and pulmonary embolism; thromboembolism with atrial fibrillation or valve replacement; after myocardial infarction

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Warfarin
- US label (DailyMed): warfarin sodium tablets: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0cbce382-9c88-4f58-ae0f-532a841e8f95
- Farge et al., 2022 international clinical practice guidelines (ITAC) for the treatment and prophylaxis of venous thromboembolism in patients with cancer (Lancet Oncol 2022): https://doi.org/10.1016/S1470-2045(22)00160-7

## Connected records

- drugs: [Enoxaparin](https://onco.cc/drugs/enoxaparin/), [Tinzaparin](https://onco.cc/drugs/tinzaparin/)
- technologies: [Cancer-associated thrombosis prevention and treatment](https://onco.cc/technologies/cancer-associated-thrombosis/)
- terms: [Venous thromboembolism (VTE)](https://onco.cc/terms/vte/)

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