Drug interactions
Aprepitant + Warfarin
Severity: Major
Aprepitant and Warfarin: major interaction.
Last updated Sources: US FDA label
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
Aprepitant can reduce warfarin effect and lower the INR, leaving patients at risk of thrombosis. The effect occurs about a week after starting aprepitant and may not be noticed without testing.
What this interaction means in plain words
Aprepitant and Warfarin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Aprepitant belongs to Gastrointestinal Tract; Warfarin belongs to Cardiovascular.
Why it happens
Aprepitant induces CYP2C9, increasing warfarin metabolism.
What to do
Monitor INR closely for about two weeks after each aprepitant course, particularly at 7 to 10 days. Adjust the warfarin dose as needed.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Aprepitant
- Aprepitant + Lomitapide Contraindicated
- Aprepitant + Pimozide Contraindicated
- Aprepitant + Avapritinib Major
- Aprepitant + Bosutinib Major
- Aprepitant + Carbamazepine Major
- Aprepitant + Cobicistat Major
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 Aprepitant with Warfarin?
MediHelp rates the interaction as major. Aprepitant and Warfarin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Aprepitant can reduce warfarin effect and lower the INR, leaving patients at risk of thrombosis. The effect occurs about a week after starting aprepitant and may not be noticed without testing.
How serious is the interaction between Aprepitant and Warfarin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor INR closely for about two weeks after each aprepitant course, particularly at 7 to 10 days. Adjust the warfarin dose as needed.
What other medicines interact with Aprepitant?
MediHelp also lists interactions of Aprepitant with, for example, Lomitapide, Pimozide, Avapritinib. The full list is on the Aprepitant page.
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