6 known interactions • 2 major • 2 moderate • 2 minor
Always disclose all medications to your healthcare providers — prescription medicines, OTC medications, vitamins, and herbal supplements. This list may not include every possible interaction. Use our Medicine Interaction Checker to screen your complete medication list.
Potentially life-threatening or causing permanent damage. Avoid combination.
May worsen condition or require dose adjustment. Monitor closely.
Usually limited clinical effect. Manage with routine monitoring.
Rilpivirine (HIV antiretroviral)
Requires gastric acid for absorption; PPIs dramatically reduce rilpivirine levels, potentially causing treatment failure.
Management: CONTRAINDICATED with rilpivirine.
Atazanavir / Nelfinavir
Requires acidic stomach for absorption; PPIs markedly reduce levels causing HIV treatment failure.
Management: Avoid combination.
Clopidogrel (Plavix)
Omeprazole inhibits CYP2C19, reducing conversion of clopidogrel to its active metabolite. This may reduce antiplatelet effect. Clinical significance debated.
Management: Consider pantoprazole as alternative PPI (least CYP2C19 inhibition). If omeprazole necessary, space doses.
Methotrexate
PPIs may increase methotrexate levels by reducing renal tubular secretion, increasing toxicity risk.
Management: Monitor for methotrexate toxicity; consider temporary PPI discontinuation during high-dose methotrexate.
Warfarin
May increase INR through unclear mechanism.
Iron supplements
Reduced gastric acid decreases non-heme iron absorption.
Always ask your pharmacist about potential interactions with food, alcohol, and supplements specific to Omeprazole. Some medicines have significant interactions with grapefruit juice, high-fat meals, dairy products, or vitamin K-rich foods.