tacrolimus - Digestion and Digestive-Related Information on MedicineNet.com Tacrolimus is a drug that suppresses the immune system and is used to prevent rejection of transplanted organs. Tacrolimus accomplishes its immune-suppressing effecting by inhibiting an enzyme (calcineurin) crucial for the multiplication of T-cells, cells that are vital to the immune process. The use of oral tacrolimus allows transplantation specialists to reduce the dose of steroids which are also used to prevent rejection. This "steroid-sparing effect" is important because of the many side effects that can occur when larger doses of steroids are used for a long period of time. Tacrolimus was approved by the FDA in April, 1994 for liver transplantation and also has been used in patients for heart, kidney, small bowel, and bone marrow transplantation.
