MAJOR — Use With Caution
🔴 AVOID — FDA 2009 safety communication: omeprazole blocks CYP2C19 activation of clopidogrel, reducing platelet inhibition. Use pantoprazole or H2 blockers instead.
Evidence level: STRONG
Omeprazole (Prilosec) can make clopidogrel (Plavix) less effective at preventing blood clots. Clopidogrel needs to be activated by a liver enzyme that omeprazole blocks. This is especially dangerous if you have a heart stent.
Omeprazole inhibits CYP2C19, which is required to convert clopidogrel (a prodrug) to its active metabolite. Reduced platelet inhibition has been demonstrated. FDA issued safety communication in 2009.
If you take Plavix, do not use Prilosec. Ask your doctor about pantoprazole (Protonix) instead — it does not block the enzyme that activates Plavix. Famotidine (Pepcid) is another safe alternative.
Take Omeprazole 30 minutes before a meal — PPIs must be activated by acid pumps that turn on when you eat. Clopidogrel can be taken with the meal or at a separate time. PPIs reduce stomach acid, which can affect absorption of many acid-dependent compounds.
Higher risk for: elderly patients, those with liver disease, history of GI bleeding, concurrent use of multiple blood thinners, recent surgery, vitamin K intake changes, alcohol use, or low body weight.
No immediate symptoms — the danger is that clopidogrel may not adequately prevent blood clots, increasing risk of heart attack or stent thrombosis
Ask about switching to pantoprazole or famotidine for stomach acid. Discuss why you need both medications and whether alternatives exist for either.
This medication combination requires careful medical oversight. Your doctor or anticoagulation clinic can adjust doses or select alternatives with fewer bleeding risks. Frequent INR monitoring is essential.
Omeprazole (Prilosec) can make clopidogrel (Plavix) less effective at preventing blood clots. Clopidogrel needs to be activated by a liver enzyme that omeprazole blocks. This is especially dangerous if you have a heart stent.
Take Omeprazole 30 minutes before a meal — PPIs must be activated by acid pumps that turn on when you eat. Clopidogrel can be taken with the meal or at a separate time. PPIs reduce stomach acid, which can affect absorption of many acid-dependent compounds.
No immediate symptoms — the danger is that clopidogrel may not adequately prevent blood clots, increasing risk of heart attack or stent thrombosis
This medication combination requires careful medical oversight. Your doctor or anticoagulation clinic can adjust doses or select alternatives with fewer bleeding risks. Frequent INR monitoring is essential.
Ask about switching to pantoprazole or famotidine for stomach acid. Discuss why you need both medications and whether alternatives exist for either.
Or browse the full interaction database (121,000+ pairs).