St John's wort induces both cytochrome P450 3A4–catalyzed sulfoxidation and 2C19–dependent hydroxylation of omeprazole

St John's wort induces both CYP3A4-catalyzed sulfoxidation and CYP2C19-dependent hydroxylation of omeprazole and enormously decreases the plasma concentrations of omeprazole. Clinically relevant interactions with other drugs may occur and must be taken into account when St John's wort is being taken.