Can You Take Omeprazole and Warfarin Together?
Omeprazole can increase warfarin's effect and bleeding risk -- named directly on omeprazole's FDA label with a monitoring recommendation.
See the full Omeprazole page and Warfarin page for other reviewed interactions and reference information.
What the interaction means
Omeprazole's FDA prescribing information has a dedicated "Warfarin" subsection stating: "Increased INR and prothrombin time in patients receiving PPIs, including omeprazole, and warfarin concomitantly. Increases in INR and prothrombin time may lead to abnormal bleeding and even death." The label's intervention: "Monitor INR and prothrombin time and adjust the dose of warfarin, if needed, to maintain target INR range."
Why it may happen
Not stated beyond the clinical impact above. Warfarin's own label separately classifies omeprazole as a CYP1A2 inducer, a category the same label elsewhere associates with the opposite effect (decreased INR) -- the two sources do not agree on a mechanism, so none is asserted here; this pair is authored strictly from omeprazole's own specific, dedicated statement about the clinical outcome and its recommended monitoring.
Practical context
Because warfarin already carries a boxed warning for bleeding risk and requires individualized INR-based dose management, the label directs monitoring INR and prothrombin time and adjusting the warfarin dose as needed during concomitant use, rather than avoiding the combination outright. Discuss any new PPI (including omeprazole) with the prescriber managing anticoagulation.
What the sources say
Last reviewed 2026-08-23
Medical information disclaimer: this information is general and educational. It does not diagnose conditions, prescribe treatment, or determine whether a combination is safe for you personally. Follow your prescription label and ask a pharmacist or clinician before starting, stopping, or combining products. Full disclaimer.
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