Warfarin and Ezetimibe: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Warfarin
Ezetimibe
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Risk of increased prothrombin time or INR
Interaction Deep Dive
Concurrent ezetimibe and warfarin therapy may result in elevated prothrombin time (PT) or international normalized ratios (INR)1. Although in 1 study of healthy adult males (n=12), coadministration of oral ezetimibe 10 mg once daily had no effect on warfarin bioavailability or PT, reports of increased INR have been noted in post-marketing surveillance. However, most of these patients were also on other medications 2. Caution is recommended if ezetimibe and warfarin are used concomitantly. Frequent monitoring of PT/INR is recommended, especially when either agent is started or stopped 12. Warfarin dosage should be adjusted accordingly.
Why it happens (mechanism)
Unknown
Common questions
Can I take Warfarin and Ezetimibe together?
Risk of increased prothrombin time or INR Always confirm with your pharmacist or prescriber before making any change.
How serious is the Warfarin and Ezetimibe interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Warfarin or Ezetimibe need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (2)
- Product Information: COUMADIN(R) oral tablets, IV injection, warfarin sodium oral tablets, IV injection. Bristol-Myers Squibb Company, Princeton, NJ, 2006. DailyMed
- Product Information: ZETIA(R) oral tablets, ezetimibe oral tablets. Merck/Schering-Plough Pharmaceuticals, North Wales, PA, 2006. DailyMed
Keep reading about Warfarin
Keep reading about Ezetimibe
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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