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Can I take Warfarin and Methotrexate together?

Drug interaction guide

Taking methotrexate while on warfarin can significantly increase your risk of bleeding. This might show up as unusual bruising, nosebleeds, bleeding gums, or in more serious cases, internal bleeding. It can also cause your blood-clotting tests (INR) to become unstable.

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Why this happens

Methotrexate can displace warfarin from the proteins in your blood that normally carry it, leaving more 'active' warfarin to thin your blood. Additionally, methotrexate can sometimes affect how the liver processes warfarin and may cause damage to the lining of the stomach or gut, which increases the risk of a bleed starting.

What you should do

You must speak to your doctor before taking these together. If you are prescribed both, you will need much more frequent blood tests (INR) to monitor how quickly your blood clots. Seek urgent medical help if you notice any signs of bleeding, such as blood in your urine, black tarry stools, or coughing up blood.

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Using other medicines

Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.

Disclaimer

This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.

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Article history

The information on this page is written and peer reviewed by qualified clinicians.

  • 24 Jan 2026 | Originally published
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