Macitentan, Oral

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KEY POINTS

• This medicine is taken by mouth to treat pulmonary hypertension. Take it exactly as directed.
• This medicine can cause severe birth defects. It must not be used by women who are pregnant.
• Keep all appointments for tests to see how this medicine affects you.
• This medicine may cause serious liver problems or other unwanted side effects. Tell your healthcare provider if you have any side effects that are serious, continue, or get worse.
• Tell all healthcare providers who treat you about all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take.

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What are other names for this medicine?

Type of medicine: endothelin receptor antagonist

Generic and brand names: macitentan, oral; Opsumit

What is this medicine used for?

This medicine is taken by mouth to treat pulmonary hypertension (high blood pressure in the lungs).

Females must be enrolled in a special program before they can receive this medicine. This medicine will be mailed to you from a special central pharmacy. It is not available through local pharmacies. Talk with your healthcare provider about this.

This medicine may be used to treat other conditions as determined by your healthcare provider.

What should my healthcare provider know before I take this medicine?

Before taking this medicine, tell your healthcare provider if you have ever had:

• An allergic reaction to any medicine
• Blood disorders (such as anemia)
• Heart failure
• Liver disease

Females of childbearing age: This medicine has been reported to cause birth defects. Read the information that comes in the medicine package. You must meet certain conditions and sign a consent form. Hormone-based forms of birth control alone may not be reliable when taking this medicine. Use a nonhormonal form of birth control such as a condom, diaphragm or sponge while taking this medicine. You must have a negative pregnancy test before you start taking this medicine. You need to have monthly pregnancy tests and use 2 forms of birth control while taking this medicine and for a month after stopping it. Talk to your healthcare provider about what forms of birth control are right for you. Stop taking this medicine at the first sign that you may be pregnant and contact your healthcare provider right away. Do not breast-feed while taking this medicine.

Males: This medicine may decrease sperm counts and make you sterile (unable to have children). If you plan to have children, talk with your healthcare provider before you start treatment.

How do I use it?

Read the Medication Guide that comes in the medicine package when you start taking this medicine and each time you get a refill.

Check the label on the medicine for directions about your specific dose. Take this medicine exactly as your healthcare provider prescribes. Do not stop taking this medicine without your healthcare provider's approval. Take the medicine at the same time each day to help you remember to take it.

Check with your healthcare provider before using this medicine in children under age 18.

You may take this medicine with or without food. Taking it with meals may lessen the chance the drug will upset your stomach. Take this medicine with a full glass of water. Swallow the tablets whole. Do not split, crush, or chew the tablets.

What if I miss a dose?

If you miss a dose, take it as soon as you remember unless it is almost time for the next scheduled dose. In that case, skip the missed dose and take the next one as directed. Do not take double doses. If you are not sure of what to do if you miss a dose, or if you miss more than one dose, contact your healthcare provider.

What if I overdose?

If you or anyone else has intentionally taken too much of this medicine, call 911 or go to the emergency room right away. If you pass out, have seizures, weakness or confusion, or have trouble breathing, call 911. If you think that you or anyone else may have taken too much of this medicine, call the poison control center. Do this even if there are no signs of discomfort or poisoning. The poison control center number is 800-222-1222.

Symptoms of an acute overdose may include: headache, nausea, vomiting.

What should I watch out for?

This medicine may cause serious liver problems. If you develop nausea, vomiting, a fever, stomach pain, unexplained loss of appetite, itching, yellowing of your eyes or skin, light-colored bowel movements, dark urine, or severe tiredness or weakness, contact your healthcare provider right away. These may be signs of a liver problem.

Avoid alcohol while taking this medicine. Alcohol may increase the risk of liver problems.

You need to have blood tests regularly to see how this medicine affects you. Keep all appointments for these tests.

If you need emergency care, surgery, lab tests, or dental work, tell the healthcare provider or dentist you are taking this medicine.

What are the possible side effects?

Along with its needed effects, your medicine may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the medicine. Tell your healthcare provider if you have any side effects that continue or get worse.

Life-threatening (Report these to your healthcare provider right away. If you cannot reach your healthcare provider right away, get emergency medical care or call 911 for help.): Allergic reaction (hives; itching; rash; trouble breathing; chest pain or tightness in your chest; swelling of your lips, tongue, and throat).

Serious (Report these to your healthcare provider right away.): Nausea, vomiting, fever, stomach pain, yellowing of your eyes or skin, dark-colored urine, light-colored bowel movements, itching, irregular or fast heartbeat, increased trouble breathing, unusual tiredness or weakness, loss of appetite, trouble urinating or pain when you urinate.

Other: Headache, cough, sore throat, stuffy nose.

What products might interact with this medicine?

When you take this medicine with other medicines, it can change the way this or any of the other medicines work. Nonprescription medicines, vitamins, natural remedies, and certain foods may also interact. Using these medicines together might cause harmful side effects. Talk to your healthcare provider if you are taking:

• Antibiotics such as clarithromycin (Biaxin), erythromycin (E.E.S., Ery-Tab, Erythrocin), rifabutin (Mycobutin), rifampin (Rifadin), rifapentine (Priftin), and telithromycin (Ketek)
• Antifungal medicines such as fluconazole (Diflucan), itraconazole (Sporanox), ketoconazole (Nizoral), posaconazole (Noxafil), and voriconazole (Vfend)
• Antiseizure medicines such as carbamazepine (Carbatrol, Epitol, Equetro, Tegretol), phenobarbital, phenytoin (Dilantin, Phenytek), and primidone (Mysoline)
• Antiviral medicines such as ombitasvir/paritaprevir/ritonavir/dasabuvir (Viekira) and ombitasvir/paritaprevir/ritonavir (Technivie)
• Cancer medicines such as ceritinib (Zykadia), crizotinib (Xalkori), dabrafenib (Tafinlar), enzalutamide (Xtandi), idelalisib (Zydelig), imatinib (Gleevec), mitotane (Lysodren), and nilotinib (Tasigna)
• Conivaptan (Vaprisol)
• Heart medicines such as diltiazem (Cardizem, Cartia, Tiazac), dronedarone (Multaq), and verapamil (Calan, Covera, Verelan)
• HIV medicines such as atazanavir (Reyataz), cobicistat (Tybost), darunavir (Prezista), efavirenz (Sustiva), elvitegravir/cobicistat/emtricitabine/tenofovir (Stribild), fosamprenavir (Lexiva), indinavir (Crixivan), lopinavir/ritonavir (Kaletra), nelfinavir (Viracept), ritonavir (Norvir), and saquinavir (Invirase)
• Lumacaftor/ivacaftor (Orkambi)
• Mifepristone (Korlym, Mifeprex)
• Nausea medicines such as aprepitant (Emend) and netupitant/palonosetron (Akynzeo)
• Nefazodone
• St. John’s wort
• Stimulants such as armodafinil (Nuvigil) and modafinil (Provigil)

Ask your healthcare provider or pharmacist if you need to avoid products that contain grapefruit, Seville oranges, and tangelos while you are taking this medicine. These fruits and juices can affect the way this medicine works and may increase your risk of serious side effects.

If you are not sure if your medicines might interact, ask your pharmacist or healthcare provider. Keep a list of all your medicines with you. List all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take. Be sure that you tell all healthcare providers who treat you about all the products you are taking.

How should I store this medicine?

Store this medicine at room temperature. Keep the container tightly closed. Protect it from heat, high humidity, and bright light.

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This advisory includes selected information only and may not include all side effects of this medicine or interactions with other medicines. Ask your healthcare provider or pharmacist for more information or if you have any questions.

Ask your pharmacist for the best way to dispose of outdated medicine or medicine you have not used. Do not throw medicine in the trash.

Keep all medicines out of the reach of children.

Do not share medicines with other people.