Macitentan lowers blood pressure in your lungs, helping your heart pump blood more efficiently.

Macitentan is used to treat pulmonary arterial hypertension (PAH). It improves your ability to exercise and prevents your condition from getting worse.

Macitentan is available to women only under a special program from a certified pharmacy. You must be registered in the program and understand the risks and benefits of taking this medication.

Macitentan may also be used for purposes not listed in this medication guide.

Do not use macitentan if you are pregnant or think you might be pregnant. Use highly effective birth control to prevent pregnancy while using macitentan and for at least 30 days after your treatment ends.

You will need to take a pregnancy test before, during, and after treatment with macitentan.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

You may take macitentan with or without food.

Swallow the tablet whole and do not crush, chew, or break it.

While using macitentan, you may need frequent blood tests.

Store at room temperature away from moisture and heat.

Usual Adult Dose for Pulmonary Hypertension:

10 mg orally once a day

Uses: For the treatment of pulmonary arterial hypertension (PAH, WHO Group I) to delay disease progression

You should not use macitentan if you are allergic to it.

Tell your doctor if you have ever had:

• liver disease;

• heart disease; or

• anemia (low red blood cells).

This medicine can harm an unborn baby or cause birth defects. Do not use macitentan if you are pregnant or think you might be pregnant. Tell your doctor right away if you miss a menstrual period or think you may have become pregnant during treatment.

You will need to have a negative pregnancy test before starting this treatment. You will be re-tested every month during your treatment, and 1 month after you stop taking this medicine.

Even if you are not planning a pregnancy, you are considered able to become pregnant if:

• you have entered puberty (even if you have not yet started having periods);

• you have never had a hysterectomy or had your ovaries removed; or

• you have not gone through menopause (you have never gone 12 months in a row without a menstrual period).

While taking macitentan and for 30 days after your last dose, you must use a highly effective form of birth control, or two methods together.

• A tubal ligation alone is an effective birth control method.

• An intrauterine device (IUD) or birth control implant alone are also effective birth control methods.

• If you use birth control pills, injections, skin patches, or vaginal rings, you must use a back-up barrier form of birth control, such as a condom or diaphragm or cervical cap. Always use a spermicide gel or insert together with a barrier form of birth control.

• If you use only a barrier method, you must use a second barrier method as a back-up. For example, use a diaphragm or cervical cap in addition to a condom, plus a spermicide gel or insert.

• If your sexual partner has had a vasectomy, you must still use a second method of birth control--either a barrier method or a hormonal form (birth control pills, injections, skin patch, or vaginal ring).

Macitentan comes with patient instructions about acceptable forms of birth control to use while taking this medicine. Follow these directions carefully. Ask your doctor or pharmacist if you have any questions.

If you are the parent or caregiver of a female child taking this medicine, talk to the child's doctor once you notice any signs of puberty (breast development or pubic hair), even if menstrual periods have not yet begun.

Macitentan can decrease sperm count and may affect fertility in men (your ability to have children).

You should not breast-feed while using this medicine.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Unless your doctor tells you otherwise, continue your normal diet.

Do not have unprotected sex while taking macitentan. You must use birth control to prevent pregnancy during treatment and for at least 30 days after you stop taking macitentan.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Macitentan may cause serious side effects. Stop using macitentan and call your doctor at once if you have:

• pain or burning when you urinate;

• swelling, rapid weight gain;

• liver problems--nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

• new lung problems--anxiety, sweating, pale skin, severe shortness of breath, wheezing, gasping for breath, cough with foamy mucus, chest pain, fast or uneven heart rate.

Common side effects of macitentan may include:

• stuffy nose, sinus pain, sore throat;

• a bladder infection;

• headache; or

• flu symptoms (fever, chills, body aches).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Other drugs may affect macitentan, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Keep all appointments with your doctor and the laboratory. Your doctor may order tests to see how well your liver is working, and to check for anemia before starting treatment and from time to time during your treatment with macitentan.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

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