Question: does grapefruit juice affect omeprazole?
Answer: The co-administration of omeprazole and grapefruit juice decreases the formation of omeprazole sulfone (mediated by CYP3A4) but does not inhibit the formation of 5-hydroxyomeprazole, which is mediated by CYP2C19. Grapefruit juice may inhibit the metabolism of pimozide resulting in increased concentrations of pimozide.