What is Tacrolimus plasma level is increased by all EXCEPT: and explain in detail?
Tacrolimus (FK506)- It is a newer immunosuppressant chemically different from cyclosporine, but having the same mechanism of action, and is 100 times more potent. It binds to a different cytoplasmic immunophilin protein labeled 'FKBP', but the subsequent steps are the same, i.e inhibition of helper T cells calcineurin. Tacrolimus is administered orally as well as by i.v. infusion. Oral absorption is variable and decreased by food. It is metabolized by CYP3A4 Section 14 and excreted in bile with a longer t1/2 of 12 hours. Among the following drugs Rifampicin is a microsomal enzyme inducer-increases several CYP450 isoenzymes including CYP3A4 .hence it enhances the metabolism of its own and other drugs that are metabolized by CYP450 like warfarin, oral contraceptives, coicosteroids, tacrolimus, etc ESSENTIALS of medical PHARMACOLOGY SEVENTH EDITION-KD TRIPATHI Page:768,878,880