How does tacrolimus contribute to immunosuppression following liver transplantation?

Updated: Dec 31, 2017
  • Author: Lemi Luu, MD, RDMS, FACEP, FAAEM; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Tacrolimus is a macrolide antibiotic produced by Streptomyces tsukubaensis. It has immunosuppressant activity similar to that of cyclosporine. Tacrolimus also inhibits calcineurin, which, in turn, results in decreased IL-2 production. Once again, T-cell recruitment and activation is dampened. The drug may produce this effect by binding to intracellular FK 506 proteins and is as much as 100 times more potent than cyclosporine in inhibiting IL-2 synthesis.

Tacrolimus, like cyclosporine, also suppresses humoral immunity through inhibition of B-cell activation by blocking IL-2 production. It is metabolized in the liver via the cytochrome P-450 system. Tacrolimus is approved for use in liver, renal, heart, bone marrow, and other transplantations, and the usual oral dosage in liver transplant recipients is 0.1-0.15 mg/kg/day. Dosing is also based on measuring blood levels, and target levels vary among institutions.

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