Adults age 18 and older may use Tracleer to treat pulmonary arterial hypertension (PAH). This prescription medicine is a type of endothelin receptor antagonist and works by blocking the action of certain proteins in the body that cause the blood vessels to constrict. Using Tracleer can help improve PAH symptoms and slow down worsening of the condition.
What Is Tracleer Used For?
Tracleer® (bosentan) is a prescription medication approved for the treatment of pulmonary arterial hypertension (PAH). It belongs to a group of medicines known as endothelin receptor antagonists.
PAH is a serious condition in which there is abnormally high blood pressure in the pulmonary arteries, the blood vessels that carry deoxygenated blood (blood without oxygen) to the lungs where the blood picks up oxygen. The oxygenated blood is then delivered to the rest of the body.
PAH begins when the pulmonary arteries become narrowed, which can happen for a variety of reasons. When the blood vessels become narrow, it makes it harder for the blood to flow through them. As a result, pressure inside the arteries increases, and the heart is forced to work harder to pump the blood through the vessels to the lungs. This puts strain on the heart. As the heart gets more and more strained, it enlarges, weakens, and eventually fails.
Symptoms of PAH begin to occur when the resistance caused by the narrowed arteries cannot be overcome and blood does not sufficiently flow through the lungs to the rest of the body. The stress on the heart also leads to symptoms. Common symptoms of the condition include:
- Shortness of breath, especially when exercising (though eventually this can occur at rest)
- Dizziness or fainting spells
- Swelling in the legs and ankles
- Chest pain
- A fast heartbeat.
One way healthcare providers assess the severity of PAH is by determining how much the symptoms limit everyday activities. They then use this information to categorize a person into one of four "functional classes."
Because the system for classifying PAH severity was developed by the World Health Organization (WHO), the categories are often referred to as WHO Classes I through IV. Interestingly, the system was adapted from a similar system developed by the New York Heart Association (NYHA) for classifying heart failure severity.
There are four functional classes. A person will move up through the classes as their disease worsens, and may move down if they respond to treatment. The four classes are as follows:
- Class I -- No limitation: There are no symptoms with exercise or at rest
- Class II -- Slight limitation: Ordinary activities cause some symptoms, but there are still no symptoms at rest
- Class III -- Marked limitation: Symptoms occur even with less-than-normal activity
- Class IV -- More severe limitation: Symptoms occur with any activity and at rest.
PAH is a progressive condition, which means it gets worse over time. Unfortunately, there is currently no cure. Instead, various treatments can be used to help relieve symptoms, improve physical functioning, and slow down disease progression. For example, diuretics may be used to reduce swelling in the legs and ankles, or oxygen may be needed to help relieve shortness of breath.
Tracleer is one of several treatments that can improve symptoms and slow down worsening of PAH. More specifically, in clinical studies, people who took this drug were able to walk farther over a six-minute period than people who did not take it (the six-minute walk test is a commonly used test to assess how much a person's PAH symptoms are limiting their ability to exercise). The medication also slows down how quickly the condition and symptoms get worse.
Clinical studies included people with functional Class II through Class IV PAH. In the studies, Tracleer did not improve walking distance in people with functional Class II symptoms. It did, however, slow down the worsening of symptoms in people with functional Class II PAH. If you have functional Class II PAH, your healthcare provider can talk to you about the risks and benefits of starting Tracleer, or delaying treatment until your symptoms get worse.