Omeprazole significantly reduces the effectiveness of clopidogrel (Plavix), a blood thinner used to prevent heart attacks and strokes. This interaction can leave patients at higher risk for cardiovascular events, including stent thrombosis in patients with coronary stents.
How This Interaction Works (Mechanism)
Clopidogrel is a prodrug that requires activation by the liver enzyme CYP2C19. Omeprazole is a potent inhibitor of CYP2C19, which blocks the conversion of clopidogrel to its active metabolite. This can reduce clopidogrel's antiplatelet activity by 40 to 50 percent, significantly diminishing its ability to prevent blood clots. The effect is most pronounced with omeprazole and esomeprazole compared to other PPIs.
Source: FDA Drug Safety Communication, 2009 (reaffirmed 2024)
Avoid omeprazole and esomeprazole while taking clopidogrel. If a proton pump inhibitor is needed, pantoprazole is the preferred alternative because it has minimal CYP2C19 inhibition. Alternatively, consider using an H2 blocker like famotidine for acid reduction. The FDA has issued a specific warning about this interaction. Discuss alternatives with your cardiologist and gastroenterologist.
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Sources and standards behind this page
What a drug interaction does, and how strongly it is supported, is documented in public labeling and federal safety references rather than in any one summary, and the sources below are the primary ones. They are linked so a reader can check a claim without taking this page's word for it.
- DailyMed carries the current FDA labeling for every marketed drug product, including the warnings and drug interaction sections.
- Drugs@FDA is the federal database of approved drug products and their approval documents.
- FDA: Drug interactions, what you should know explains how drug-drug, drug-food and drug-condition interactions are described on labels.
- FDA Drug Safety Communications publishes the agency's safety alerts and label changes as they are issued.
- FDA MedWatch is the program for reporting and reviewing adverse events, including suspected interactions.
- openFDA provides public access to FDA labeling and adverse event data.
- MedlinePlus drug information is the National Library of Medicine's consumer reference for what a medicine is and how it is taken.
- NIAAA: Harmful interactions documents which medicines interact with alcohol and how.
- NCCIH: Herb-drug interactions summarises the evidence on interactions between herbal products and medicines.
- National Library of Medicine maintains the drug and health databases the sources above draw on.
This page describes how this interaction works and where it is documented. It is not medical advice: a prescriber or pharmacist decides what applies to a particular patient and medication.
Frequently Asked Questions
Omeprazole and Clopidogrel have a severe interaction and should generally not be taken together without close medical supervision. The combination can cause serious, potentially life-threatening side effects. Contact your doctor immediately if you are currently taking both medications.
Omeprazole significantly reduces the effectiveness of clopidogrel (Plavix), a blood thinner used to prevent heart attacks and strokes. This interaction can leave patients at higher risk for cardiovascular events, including stent thrombosis in patients with coronary stents.
Yes. Anytime you are taking multiple medications, supplements, or substances, you should inform your doctor and pharmacist. They can evaluate your specific risk factors (age, kidney function, other medications, medical conditions) and determine whether the Omeprazole and Clopidogrel combination is safe for you, or whether adjustments are needed.
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