Skip to contentSkip to navigation
COVID-19: We are open. Some services are modified. Mask is mandatory. Details at


Tacrolimus (FK506, Prograf, etc.) is a drug that decreases immune system response. It is used alone or in combination with other drugs to prevent transplant rejection in transplant programs. Tacrolimus is metabolized by the liver, and several drugs can increase (anticonvulsants, rifampin) or decrease (calcium channel blockers, antifungal agents, some antibiotics, grapefruit juice) effective blood levels of tacrolimus. Desirable tacrolimus levels vary depending on the type of transplant, risk of rejection, length of time since transplantation, use of other immunosuppressive drugs and side effects. The lowest blood levels between two doses are measured, usually 12 hours after the last dose, or immediately before the next dose of the drug. Results are expressed in micrograms of tacrolimus per litre of whole blood (µg/L).

In the long term, optimal blood levels of tacrolimus are generally kept between 5.0 and 15.0 µg/L. However, higher levels are desired immediately after transplantation and are gradually reduced in stable patients. In the longer term, levels below 20 µg/L are desirable to avoid significant side effects of the drug.

Term of the Week

Hot zone

A hot zone is a section of a facility (sometimes an entire facility or even a city district) where there is a high risk of contamination by patients with an infectious disease. All individuals entering a hot zone must respect appropriate protective measures. By analogy, “cold zone” and “warm zone” are used to refer to areas where there is no infected individual or only individuals suspected of having an infection.