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Opsumit

Generic Name: macitentan (MA-si-TEN-tan)
Brand Name: Opsumit

Opsumit may cause serious birth defects if you take it while you are pregnant. Women who are pregnant should not take Opsumit. You must have a negative pregnancy test before you start to take Opsumit, monthly while you take it, and for 1 month after you stop taking it. You must also use effective forms of birth control while you take Opsumit and for 1 month after you stop taking it. Talk with your doctor about the use of effective birth control while you use Opsumit.

For female patients, Opsumit is only available through a special program called Opsumit Risk Evaluation and Mitigation Strategy Program (REMS). Talk to your doctor to be sure you are enrolled in this program and that you meet all of its requirements.


Opsumit is used for:

Treating high blood pressure in the lungs (pulmonary arterial hypertension [PAH]) in certain patients.

Opsumit is an endothelin receptor antagonist. It works by blocking a certain substance in the lungs, which helps to decrease blood pressure in the lungs.

Do NOT use Opsumit if:

  • you are allergic to any ingredient in Opsumit
  • you are pregnant, may become pregnant, or plan to become pregnant
  • you have severe anemia
  • you are taking mifepristone, nefazodone, St. John's wort or certain medicines that are used for cancer, hepatitis C, HIV, infections, or seizures. Ask your doctor or pharmacist if you are unsure if any of your medicine should not be taken with Opsumit

Contact your doctor or health care provider right away if any of these apply to you.

Before using Opsumit:

Some medical conditions may interact with Opsumit. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are able to become pregnant
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have a history of liver problems, heart failure, or anemia
  • if you have fluid retention (eg, unusual swelling of the arms, hands, legs, or feet) or a certain lung problem called pulmonary veno-occlusive disease (PVOD)

Some MEDICINES MAY INTERACT with Opsumit. Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Mifepristone, nefazodone, St. John's wort or certain medicines that are used for cancer, hepatitis C, HIV, infections, or seizures. Ask your doctor or pharmacist if you are unsure if any of your medicines might interact with Opsumit

This may not be a complete list of all interactions that may occur. Ask your health care provider if Opsumit may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Opsumit:

Use Opsumit as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Opsumit comes with an extra patient information sheet called a Medication Guide. Read it carefully. Read it again each time you get Opsumit refilled.
  • Take Opsumit by mouth with or without food.
  • Swallow Opsumit whole. Do not break, split, crush, or chew before swallowing.
  • Take Opsumit on a regular schedule to get the most benefit from it. Taking Opsumit at the same time each day will help you to remember to take it.
  • Continue to take Opsumit even if you feel well. Do not miss any doses.
  • If you miss a dose of Opsumit, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Opsumit.

Important safety information:

  • Do NOT take more than the recommended dose, change your dose, or stop taking Opsumit without checking with your doctor.
  • Serious liver problems have been reported with other medicines that are similar to Opsumit (eg, bosentan). Contact your doctor right away if you develop symptoms of liver problems, such as nausea, vomiting, loss of appetite, fever, stomach pain, yellowing of the skin or eyes, dark urine, pale stools, itching, or unusual tiredness or achiness. Discuss any questions or concerns with your doctor.
  • Some men taking another medicine similar to Opsumit (bosentan) have experienced a decrease in sperm count. A low sperm count may decrease the ability to father a child. It is not known if Opsumit may cause the same effect on sperm count. Discuss any questions or concerns with your doctor.
  • Women who are able to become pregnant must have a negative pregnancy test before they start to take Opsumit, monthly while they are taking it, and for 1 month after they stop taking it. Talk with your doctor for more information.
  • Women who are able to become pregnant must use effective forms of birth control while they take Opsumit and for at least 1 month after they stop taking it. Talk with your doctor about the use of effective birth control while you use Opsumit. Talk with your doctor right away if you miss a menstrual period, have unprotected sex, think your birth control has failed, or think you may be pregnant.
  • Tell your doctor or dentist that you take Opsumit before you receive any medical or dental care, emergency care, or surgery.
  • Lab tests, including liver function, hemoglobin levels, and hematocrit levels, may be performed while you use Opsumit. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
  • Opsumit should be used with extreme caution in CHILDREN; safety and effectiveness in children have not been confirmed.
  • PREGNANCY and BREAST-FEEDING: Do not take Opsumit if you are pregnant. It may cause harm to the fetus. Avoid becoming pregnant while you are taking it. If you think you may be pregnant, contact your doctor right away. It is not known if this medicine is found in breast milk. Do not breast-feed while taking Opsumit.

Possible side effects of Opsumit:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Headache; sore throat; stuffy nose.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue; unusual hoarseness); difficult or painful urination; flu-like symptoms (eg, headache, tiredness, muscle aches, fever, chills); new or worsening shortness of breath; new or worsening swelling of the hands, legs, ankles, and feet; severe or persistent cough; sudden or unusual weight gain; unusual tiredness or weakness.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately.

Proper storage of Opsumit:

Store Opsumit between 68 and 77 degrees F (20 and 25 degrees C) in the original package. Store away from heat, moisture, and light. Do not store in the bathroom. Keep Opsumit out of the reach of children and away from pets.

General information:

  • If you have any questions about Opsumit, please talk with your doctor, pharmacist, or other health care provider.
  • Opsumit is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.
  • Check with your pharmacist about how to dispose of unused medicine.

This information should not be used to decide whether or not to take Opsumit or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about Opsumit. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to Opsumit. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your health care provider for complete information about the risks and benefits of using Opsumit.

Review Date: November 3, 2016

Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using this medicine.

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