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OPSUMIT helps open blood vessels between the heart and lungs

When you have PAH, your body may produce too much of a substance called endothelin. This can cause the blood vessels in your lungs to narrow, restricting blood flow and putting strain on the heart. OPSUMIT targets the endothelin pathway specifically, and works to open these narrow blood vessels.

OPSUMIT helped patients walk farther

Improvement was measured by the 6-minute walk distance (6MWD), a test that measures the distance you can walk in 6 minutes. It is one test that your doctor may perform to assess your condition.

OPSUMIT improved patients’ ability to do more physical activity

More patients taking OPSUMIT saw an improvement of at least one functional class. At Month 6 in the clinical trial, 22% of patients taking OPSUMIT improved their functional class compared with 13% of patients not taking it.

OPSUMIT reduced the risk of PAH progression

Patients taking OPSUMIT were 45% less likely to have their PAH progress than patients not taking it.

OPSUMIT lowered the chance of being hospitalized due to PAH

The most important information about OPSUMIT® (macitentan)

Do not take OPSUMIT if you are pregnant or trying to get pregnant. OPSUMIT can cause serious birth defects if taken while pregnant.

Women who are able to get pregnant must have negative pregnancy tests:

  • Before starting OPSUMIT
  • Each month while taking OPSUMIT
  • For 1 month after stopping OPSUMIT

Your doctor will decide when you should take pregnancy tests.


  • With OPSUMIT, dosing is convenient
  • OPSUMIT® (macitentan) is a once-daily pill
  • You can take it with or without food
  • OPSUMIT can be taken alone or in combination with PDE-5 inhibitors or inhaled prostanoids, which are types of PAH medicines.

How to take OPSUMIT

  • Take OPSUMIT exactly as your doctor recommends
  • Do not stop taking OPSUMIT unless you’re advised to do so by your doctor
  • You can take OPSUMIT with or without food
  • Do not split, crush, or chew OPSUMIT tablets
  • If you miss a dose of OPSUMIT, take it as soon as you remember that same day. You can take the next dose of OPSUMIT at your regular time. Do not take 2 doses at the same time to make up for a missed dose
OPSUMIT Side Effects
  Side Effect Severity Mild Moderate Severe
Likely (>10%)

Nasopharyngitis/Pharyngitis (20%)

Headache (14%)

Bronchitis (12%)

Anemia (13%)
Less Likely (1-10%) Influenza/Influenza like symptoms (6%) Urinary Tract Infection (9%)
Rare (<1%)

You need to be prepared to work through possible adverse effects.
Headaches can be treated with Tylenol (Acetaminophen).
If urinary tract infections or bronchitis occur, please contact your clinician.
Regular lab-work will monitor for anemia (Low blood counts)

Starting a New Medication

When you are prescribed OPSUMIT:

  • You and your doctor will review important information, including the OPSUMIT Medication Guide, and complete the OPSUMIT Prescription Statement of Medical Necessity (PSMN) form. You should also ask questions about OPSUMIT at this time
  • If you are a woman, you must enroll in the Opsumit Risk Evaluation and Mitigation Strategy (REMS) Program, due to the risk of serious birth defects. You must agree to all instructions in the program
  • If you are a woman who can get pregnant, you must also:
    • Review the Opsumit REMS Guide for Female Patients
    • Have a negative pregnancy test before starting OPSUMIT, each month while taking OPSUMIT, and for 1 month after you stop taking OPSUMIT
    • Use acceptable forms of birth control when taking OPSUMIT and for 1 month after stopping OPSUMIT. Acceptable birth control options are included in the OPSUMIT Medication Guide. Your doctor will help you choose the types of birth control that are right for you

Actelion provides a wide range of support and education options through Actelion Pathways. If you choose to enroll, your Actelion Pathways Case Manager will call you to:

  • Help answer your questions about filling your prescription
  • Coordinate with your healthcare team, insurance company, and specialty pharmacy to help find out if you have coverage for your medicine
  • Share information about possible financial assistance programs to determine your eligibility

OPSUMIT is not available at your local retail pharmacy and is only available through a specialty pharmacy, which will send your medicine to your home. When OPSUMIT arrives at your home, take OPSUMIT as prescribed by your doctor.
The specialty pharmacy may not ship your medicine if they don’t speak with you first. Be sure to answer when they call and call them back if they leave a message.

  • Each month, your specialty pharmacy will call you to review your current medicines, discuss the OPSUMIT Medication Guide, and reorder OPSUMIT
    • OPSUMIT can be shipped in as little as 24 hours once your enrollment is confirmed with an Actelion Pathways Case Manager and a specialty pharmacist
  • If you are a woman who is able to get pregnant:
    • You need to use 2 acceptable forms of birth control and take pregnancy tests as recommended by your doctor. Do not get pregnant. Tell your doctor right away if you have unprotected sex, think that your birth control has failed, miss a menstrual period, or think you are pregnant
    • Be ready to talk about your monthly pregnancy test results with your specialty pharmacy
    • The refill may not be done on time if you have not had your pregnancy test
Financial Support

OPSUMIT Prescription Assistance

Actelion provides a wide range of support and educational tools through Actelion Pathways®

After you’re prescribed OPSUMIT, you can be enrolled to receive:

Prescription Answers
Answers to questions about filling your prescription.


Healthcare Coordination
Help coordinating with your healthcare provider, insurance company, and specialty pharmacy to find out if you have coverage for your medicine.


Financial Assistance Information
Information about possible financial assistance programs, based on your eligibility.


A 30-Day Free Trial of OPSUMIT
A 30-day free trial of OPSUMIT through the OPSUMIT Voucher Program. Eligible patients over 18 can request a free trial from an Actelion Pathways Case Manager during enrollment. This offer is only valid for the first 30-day supply of OPSUMIT. Patients must agree to the Terms and Conditions.


Patient Support

Support from our PAH Companions

Actelion Pathways® PAH Companion* Program provides one-on-one educational support to help you start and stay on your prescribed Actelion medication and resources to help you partner with your healthcare team to better manage your pulmonary arterial hypertension (PAH). Look to the Actelion Pathways® PAH Companion for:

  • Tools to help you have more productive discussions with your healthcare team
  • Tips for engaging with your support network (friends, family, and peers)
  • Ongoing education on managing and living with PAH
  • Connection with a dedicated PAH Companion* through email, phone, and/or text

As part of the program, Actelion Pathways® PAH Companions* are ready to answer your questions. Patients who have enrolled can talk to a PAH Companion* by calling 1-866-300-1818, Mon-Fri, 8 AM-9 PM ET.

Patient Support Groups

Through Pulmonary Hypertension Association, find a support group close to you.



Pulmonary Arterial Hypertension is a serious condition. The medications designed to fight the disease typically show benefit slowly, over months, with most needing 4 to 6 months for maximum effect. The adverse effects (Side-effects) of these medications, however happen upfront. Your body typically will get used to them either with time, or with additional natural remedy or drugs. This may also take 2 to 3 months. It is necessary that you have patience, and talk to your doctor or nurses about dealing with them. Sometimes slowing the planned increase or cutting down on medication for a while will allow your body to adjust. Discuss matters with your doctors’ office before taking action of your own. Patience is a virtue!

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