Tacrolimus lowers your body's immune system. The immune system helps your body fight infections. The immune system can also fight or "reject" a transplanted organ such as a liver or kidney. This is because the immune system treats the new organ as an invader.

Tacrolimus is used together with other medicines to prevent your body from rejecting a heart, liver, or kidney transplant.

Tacrolimus may also be used for purposes not listed in this medication guide.

Treatment with tacrolimus may increase your risk of developing certain life-threatening conditions, including serious infections, cancer, or transplant failure. Talk with your doctor about the risks and benefits of using this medication.

You will need regular medical tests to be sure this medication is not causing harmful effects. Do not miss any follow up visits to your doctor for blood or urine tests. Avoid being near people who are sick or have infections.

Tacrolimus can harm your kidneys, and this effect is increased when you also use certain other medicines harmful to the kidneys. Before using tacrolimus, tell your doctor about all other medicines you use. Many other drugs (including some over-the-counter medicines) can be harmful to the kidneys.

Some people receiving tacrolimus after a kidney transplant have developed diabetes, most often in people who are Hispanic or African-American. Talk with your doctor about your individual risk of diabetes.

You should not use this medication if you are allergic to tacrolimus or hydrogenated castor oil, or if you have used cyclosporine (Neoral, Sandimmune, Gengraf) within the past 24 hours.

Tacrolimus can lower blood cells that help your body fight infections, or cause your body to produce too much of a certain type of white blood cells. This can lead to serious and sometimes fatal conditions, including cancer, a severe brain infection that can lead to disability or death, or a virus that can cause failure of a transplanted kidney.

Call your doctor right away if you have symptoms of a serious brain infection, such as a change in your mental state, problems with speech or walking, or decreased vision. These symptoms may start gradually and get worse quickly.

Using tacrolimus may increase your risk of developing skin cancer, especially if you are treated over long periods of time with drugs that weaken the immune system. Talk with your doctor about your specific risk.

Some people taking tacrolimus after a kidney transplant have developed diabetes. This effect has been seen most often in people who are Hispanic or African-American. Talk with your doctor about your individual risk of diabetes if you have concerns.

To make sure you can safely take tacrolimus, tell your doctor if you have any of these other conditions:

• kidney or liver disease;

• high blood pressure;

• liver disease;

• high cholesterol or triglycerides (a type of fat in the blood); or

• if you are using other drugs that weaken your immune system such as cancer medicine or steroids.

FDA pregnancy category C. It is not known whether tacrolimus will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.

Tacrolimus can pass into breast milk and may harm a nursing baby. You should not breast-feed while you are using tacrolimus.