Moderate
Probable
Descripción
Omeprazole inhibits CYP2C19 and weakly inhibits CYP3A4, leading to modest increases in tacrolimus exposure particularly in CYP2C19 poor metabolisers.
Mecanismo
Tacrolimus is a minor CYP2C19 substrate; omeprazole's potent CYP2C19 inhibition reduces a secondary metabolic pathway, with the magnitude dependent on the patient's CYP2C19 genotype.
Relevancia clínica
In CYP2C19 poor metabolisers, tacrolimus trough increases of 20–40% have been reported; this is generally less pronounced than with strong CYP3A4 inhibitors.
Manejo clínico
Monitor tacrolimus trough levels when initiating or discontinuing omeprazole, particularly in patients with known or suspected CYP2C19 poor-metaboliser status; pantoprazole is a lower-risk alternative.