FK 506 (Tacrolimus or Prograf)

General Information

Tacrolimus (FK506) is an immunosuppressive drug that is given orally or intravenously to patients who have had a kidney, liver, heart, or other organ transplant. Normally, a person’s immune system would recognize the new organ as foreign and begin to attack it. Tacrolimus limits this response and helps to prevent organ rejection by reducing the activity of T-lymphocytes. Therefore levels may be measured in order to establish the correct dose, maintain therapeutic levels and detect toxic levels

Generally, the lower the level the better, provided the patient is NOT rejecting. There is a significant clinical component in the interpretation of results.

It is important to monitor levels of tacrolimus for several reasons:

There is not a good correlation between the dose of tacrolimus given and level of drug in the blood.

Absorption and metabolism of oral doses of tacrolimus can vary greatly between patients and even in the same patient depending on the time of the dose and what, if any food has been eaten.

Tacrolimus can cause kidney damage, especially in high doses. Measuring levels in patients who have had a kidney transplant may help to distinguish between kidney rejection (levels are low) and kidney damage due to tacrolimus toxicity (levels are high).

Tacrolimus monitoring helps ensure that each individual is receiving the right amount of drug needed to treat his or her particular case.

NOTE From Monday 16th January 2017 all tacrolimus samples will be processed in-house by tandem mass spectrometry