Do grapefruit juice and omeprazole interact?

Yes. Grapefuit and grapefruit juice have the potential to interact with numerous drugs. They interfere with hepatic and intestinal enzyme cytochrome p450 isoform cyp3a4 and are believed to be primarily responsible for the effects of grapefruit on the enzyme. Omeprazole (prilosec) is one of the drugs that is affected.