Letairis and Pregnancy
As a pregnancy Category X medication, Letairis (ambrisentan) should not be used during pregnancy. Studies have shown that the potential risks of using this drug while pregnant clearly outweigh the benefits. When this drug was given to pregnant animals, it caused various birth defects. Women who take Letairis must follow certain steps to prevent pregnancy during treatment.
Letairis® (ambrisentan) may cause birth defects if taken during pregnancy. Therefore, this medication should not be used in women who are or who may become pregnant.
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. Letairis is classified as a pregnancy Category X medication.
Pregnancy Category X is given to medicines that cause fetal problems in animal studies or in human use of the medication. With this category, the potential risks clearly outweigh the potential benefits.
Letairis has not been studied in pregnant women. In animal studies, the drug increased the risk for birth defects when given to pregnant rats and rabbits. More specifically, it caused defects of the jaw, mouth, heart, blood vessels, thymus (a gland of the immune system), and thyroid gland.
Because this medication can cause fetal harm, it is only available through a restricted program. You, your healthcare provider, and the pharmacy that sends you the medicine must be enrolled in this program. By enrolling in the program, you agree to follow the instructions for using this medication. If you are able to get pregnant, this includes having a negative pregnancy test prior to starting Letairis treatment, and each month you take the medication. This is to make sure you are not pregnant, as pregnant women must not use Letairis.
Women of childbearing potential should use reliable birth control to prevent pregnancy during Letairis treatment, and for at least one month after treatment ends. Women who have a tubal sterilization, or who use a copper intrauterine device (IUD) or certain levonorgestrel-releasing intrauterine system birth control (such as Mirena®) can rely on these methods alone. Other women should use two forms of birth control.
The two forms of birth control a woman chooses should include either one hormonal and one barrier method or two barrier methods. Examples of hormonal birth control include:
- Birth control pills (oral contraception)
- The birth control patch (norelgestromin/ethinyl estradiol)
- NuvaRing® (etonogestrel/ethinyl estradiol vaginal ring)
- Depo-Provera® (medroxyprogesterone intramuscular injection).
Examples of barrier methods of birth control include:
- A diaphragm with spermicide
- A cervical cap with spermicide
Talk to your healthcare provider about which reliable forms of birth control may be best for your particular situation. Also, let your healthcare provider know right away if you suspect your birth control may have failed or if you had unprotected sex. He or she may recommend emergency contraception.
Because birth defects from Letairis can happen early in pregnancy, it is important to contact your healthcare provider right away if you have a late menstrual period or if you suspect you may be pregnant. You and your healthcare provider can discuss the potential risks to you and your unborn child.