Tacrolimus and Pregnancy
During animal studies, giving high doses of tacrolimus to pregnant rats and rabbits appeared to cause miscarriages, fetal birth defects, and other problems. As a result, the FDA has classified tacrolimus as a pregnancy Category C medicine, which means that the drug may not be safe for use during pregnancy and should only be used when the benefits outweigh the risks.
Tacrolimus (Prograf®, Protopic®) is a prescription medication used to prevent organ rejection in people who have received a heart, kidney, or liver transplant. A topical form of tacrolimus is approved to treat atopic dermatitis (eczema). This medicine may not be safe for use during pregnancy.
Tacrolimus is classified as a pregnancy Category C drug. The U.S. Food and Drug Administration (FDA) uses a category system to classify the possible risks to a fetus when a specific medicine is taken during pregnancy. Pregnancy Category C is given to medicines that have not been adequately studied in pregnant humans but have caused fetal harm in animal studies.
In addition, medicines that have not been studied in any pregnant women or animals are automatically given a pregnancy Category C rating.
In animal studies, tacrolimus increased the risk for miscarriage when given orally (by mouth) to pregnant rats and rabbits at doses high enough to cause side effects in the mother animals. The drug also caused fetal birth defects, including heart, bone, and gallbladder problems, when given in very high doses to pregnant rats and rabbits.
However, it is important to note that animals do not always respond to medicines in the same way that humans do. Therefore, a pregnancy Category C medicine may be given to a pregnant woman if her healthcare provider believes that the benefits to the woman outweigh any possible risks to her unborn child.
The use of immunosuppressants during pregnancy, including tacrolimus, has been associated with premature delivery, as well as kidney problems and increased blood potassium levels (hyperkalemia) in the newborn infant. In the majority of these cases, the women were taking tacrolimus to prevent organ rejection after a kidney transplant. There are also many cases of the medicine being used safely during pregnancy, with no adverse problems noted in the newborn babies.
Tacrolimus ointment is applied directly on the skin, and only a small amount is absorbed into the bloodstream after normal use. Therefore, the ointment is probably safer to use during pregnancy, compared with the oral or injectable forms. However, certain factors may increase the amount of medicine absorbed through the skin, such as using the medicine more often than recommended or applying it to large areas of skin or on skin that has open sores. Also, people with certain skin conditions may absorb more tacrolimus than normally expected.