Macitentan (trade name: Opsumit) has been approved in Germany since December 2013 for the treatment of pulmonary arterial hypertension (high blood pressure) in adults. This drug can be combined with other blood-pressure-lowering (antihypertensive) medications.

The right side of the heart pumps blood that is low in oxygen through the pulmonary artery into the lungs. The blood picks up oxygen in the lungs and then travels through the pulmonary vein to the left side of the heart. From there, oxygen-rich blood is pumped into the body. This part of the blood circulatory system is called pulmonary circulation. In pulmonary arterial hypertension, the pulmonary (lung) vessels are narrowed, increasing the blood pressure within the pulmonary circulation. This makes it harder for the heart to pump blood through the lungs. As a result, there is more strain on the heart, less oxygen is absorbed by the lungs, and too little oxygen reaches the body. This type of high blood pressure is usually caused by another heart or lung condition.

There are four stages of pulmonary arterial hypertension (PAH), described by the WHO as "functional classes":

  • Functional class I: Patients have an increased pulmonary blood pressure, but have no symptoms during normal physical activity.
  • Functional class II: During physical activity, patients have symptoms such as trouble breathing, fatigue, chest pain or feeling faint. These symptoms stop when resting.
  • Functional class III: Even light physical activity causes severe symptoms, but there are no symptoms at rest.
  • Functional class IV: Symptoms occur even at rest and physical activity is severely limited. There is also a risk of heart failure.

Macitentan is an option for people with functional class II or III pulmonary arterial hypertension. The drug aims to widen the blood vessels and to decrease the strain on the heart.


The drug is taken once a day in tablet form at a dose of 10 mg. It should always be taken at about the same time of day.

Other treatments

For people with pulmonary arterial hypertension, the standard treatment is what is known as optimized drug treatment. The exact type of individual treatment will depend on whether it is an initial treatment or which treatments have been tried before. The treatment is individually adjusted by the doctor.


In 2016, the Institute for Quality and Efficiency in Health Care (IQWiG, Germany) wanted to look into the advantages and disadvantages of macitentan compared with the standard treatments for people with pulmonary arterial hypertension.

However, the manufacturer did not provide any suitable data with which to do the assessment.

More information

This information summarizes the main results of a review produced by the Institute for Quality and Efficiency in Health Care (IQWiG, Germany). The review was commissioned by the German Federal Joint Committee (G-BA) as part of the “early benefit assessment of medications.” On the basis of the review and the hearings received, the G-BA passed a resolution on the added benefit of macitentan (Opsumit).