Rapamune and Pregnancy
The immunosuppressant Rapamune (sirolimus) is a pregnancy Category C drug, which means it may be used if the benefits outweigh the risks. However, the manufacturer of the drug recommends that if you are not pregnant, you should use an effective form of birth control before and during treatment. Birth control should also be continued for at least 12 weeks after treatment ends.
Rapamune® (sirolimus) is a prescription medication used in combination with other medicines to prevent rejection after a kidney transplant. It is in a class of drugs known as immunosuppressants. Based on the results of animal studies, this medication may not be safe for use during pregnancy.
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 studied in pregnant humans but do appear to cause harm to the fetus 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, the drug did not cause birth defects when given to pregnant rats and rabbits, but did cause low fetal weight and miscarriage in the rats. Rapamune is initially used in combination with cyclosporine (Gengraf®, Neoral®, Sandimmune®) after a kidney transplant. The risk for miscarriage was even higher when rats were given both medicines, as compared to Rapamune alone.
However, it is important to note that animals do not always respond to medicines the same way that humans do. Therefore, a pregnancy Category C drug may be given to a pregnant woman if the healthcare provider believes that the benefits to the woman outweigh any possible risks to the unborn child.
There is very limited information on the use of Rapamune during pregnancy. The medication has not been studied in pregnant women. There are a few reported cases of women who used the medicine, in addition to other immunosuppressants, while pregnant without serious problems. However, it is not possible to fully assess the risk of Rapamune use during pregnancy based on such little information.
The manufacturer recommends that women of childbearing potential use an effective form of birth control before and during treatment and for at least 12 weeks after treatment ends. Your healthcare provider can help you choose the best birth control option for your individual situation.