Can I take Warfarin and Methotrexate together?

Taking warfarin and methotrexate together should be done with caution as taking them together can significantly increase your risk of bleeding.

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.

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.

You may be experiencing an interaction between warfarin and methotrexate if:

• You notice unusual bruising or bleeding, such as nosebleeds or bleeding gums.

• You have blood in your pee (urine) or poo (stools), or have black, tarry poo.

• You feel unusually tired, weak, or dizzy.

• You develop mouth ulcers or a sore throat.

• You have signs of infection, such as fever or chills.

• Your blood tests show a raised INR or changes in blood counts.
  

If you have any of the above symptoms, you should:

• Contact your GP or anticoagulation clinic for advice as soon as possible.

• Seek urgent medical help if you have heavy bleeding or bleeding that will not stop.

• Do not stop taking warfarin or methotrexate suddenly unless advised by a healthcare professional.

• Attend any blood tests arranged to check your INR or blood counts.

Tell your healthcare professional about all medicines, supplements, and herbal remedies you are taking.

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.