tacrolimus

Meaning of tacrolimus: Tacrolimus suppresses the immune system by blocking a step in T cell activation, and is used mainly to prevent rejection after organ transplantation.

Definition of tacrolimus

Tacrolimus is a medication that suppresses the activity of the immune system, belonging to a class of drugs called calcineurin inhibitors. It works by blocking calcineurin, an enzyme involved in activating T cells, a type of white blood cell central to the immune response that would otherwise recognize transplanted tissue as foreign.

Tacrolimus is used most often to help prevent the body's immune system from rejecting a transplanted organ or bone marrow, and it is typically given together with other immunosuppressive medications as part of a broader regimen following transplantation. It is also used in certain other conditions involving an overactive immune response.

Because tacrolimus suppresses immune activity broadly rather than only the specific response responsible for transplant rejection, its use requires ongoing monitoring of blood drug levels and increases susceptibility to infection, effects that are weighed against the benefit of preventing organ rejection.