Drug interactions
Methotrexate + Warfarin
Severity: Moderate
Methotrexate and Warfarin: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Methotrexate may alter anticoagulant response to warfarin, and reported effects include raised INR. Methotrexate can also cause liver injury or thrombocytopenia, which add to bleeding risk.
What this interaction means in plain words
Methotrexate and Warfarin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Methotrexate belongs to Oncology; Warfarin belongs to Cardiovascular.
Why it happens
Not clearly established; possible protein-binding displacement and methotrexate-related hepatic or hematologic effects.
What to do
Monitor INR more often when starting, changing or stopping methotrexate. Adjust the warfarin dose as needed and watch for bleeding.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Methotrexate and Warfarin, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Methotrexate
- Acitretin + Methotrexate Contraindicated
- Adenovirus types 4 and 7 live + Methotrexate Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Methotrexate Contraindicated
- Ketorolac + Methotrexate Contraindicated
- Measles mumps and rubella vaccine live + Methotrexate Contraindicated
- Measles mumps and rubella vaccine + Methotrexate Contraindicated
Other interactions of Warfarin
- Defibrotide + Warfarin Contraindicated
- Ketorolac + Warfarin Contraindicated
- Abciximab + Warfarin Major
- Acetylsalicylic acid + Warfarin Major
- Adagrasib + Warfarin Major
- Amiodarone + Warfarin Major
Frequently asked questions
Can I take Methotrexate with Warfarin?
MediHelp rates the interaction as moderate. Methotrexate and Warfarin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Methotrexate may alter anticoagulant response to warfarin, and reported effects include raised INR. Methotrexate can also cause liver injury or thrombocytopenia, which add to bleeding risk.
How serious is the interaction between Methotrexate and Warfarin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor INR more often when starting, changing or stopping methotrexate. Adjust the warfarin dose as needed and watch for bleeding.
What other medicines interact with Methotrexate?
MediHelp also lists interactions of Methotrexate with, for example, Acitretin, Adenovirus types 4 and 7 live, Influenza virus vaccine quadrivalent intranasal. The full list is on the Methotrexate page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
