Drug interactions
proton pump inhibitor + warfarin
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.
Overview
PPIs—especially omeprazole/esomeprazole—may enhance warfarin effect with reports of increased INR and bleeding; impact varies by specific PPI (pantoprazole has lower potential).
Mechanism of action
Some PPIs inhibit CYP2C19 (and slightly CYP2C9), decreasing warfarin clearance (mainly R-warfarin) → increased anticoagulant effect and INR; magnitude varies by PPI.
Clinical management
If coadministered, check INR within 3–7 days of PPI initiation, discontinuation, or dose change; adjust warfarin as needed. Prefer pantoprazole if a PPI is required; counsel on bleeding signs.
Drug reference
References
- Omeprazole (Prilosec) Prescribing Information — FDA Label
- Esomeprazole (Nexium) Prescribing Information — FDA Label
- Pantoprazole Sodium (Protonix) Prescribing Information — FDA Label
Frequently asked questions
Can I take proton pump inhibitor with warfarin?
The interaction is rated: Moderate. PPIs—especially omeprazole/esomeprazole—may enhance warfarin effect with reports of increased INR and bleeding; impact varies by specific PPI (pantoprazole has lower potential).
How serious is the interaction between proton pump inhibitor and warfarin?
The interaction is rated: Moderate. Evidence level: High.
How is the interaction between proton pump inhibitor and warfarin managed?
If coadministered, check INR within 3–7 days of PPI initiation, discontinuation, or dose change; adjust warfarin as needed. Prefer pantoprazole if a PPI is required; counsel on bleeding signs.
Why do proton pump inhibitor and warfarin interact?
Some PPIs inhibit CYP2C19 (and slightly CYP2C9), decreasing warfarin clearance (mainly R-warfarin) → increased anticoagulant effect and INR; magnitude varies by PPI.
Full monographs, dosing and an interaction checker in the MediHelp app
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