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What is Bosentan?

D. Jeffress
D. Jeffress

Bosentan is a prescription oral medication used to treat symptoms of pulmonary arterial hypertension, or high blood pressure in the arteries that supply the lungs. It relaxes and expands blood vessels in the chest, making it easier for blood to flow freely. Patients who take bosentan exactly how it is prescribed and follow their doctors' orders about diet and exercise generally start to see symptom improvement in as little as one month. There are slight chances of experiencing side effects and health complications when taking the drug, so frequent health checkups are recommended during treatment to minimize risks.

Pulmonary arterial hypertension is a fairly common problem, especially among older adults and those who suffer from obesity and diabetes. Patients with the disorder have elevated levels of a chemical called endothelin in their bodies that triggers blood vessel constriction. Bosentan works by blocking the activity of endothelin in pulmonary blood vessels, allowing smooth muscle tissue to expand. With the blood vessels dilated, the heart has an easier time pumping blood to the lungs.


Before prescribing bosentan, a doctor will usually ask a series of health questions and perform blood tests to make sure the drug will be safe to use. Relatively healthy adults who have not experienced allergic reactions to similar medications in the past are the generally best candidates for bosentan. Exact dosing amounts depend on several factors, but most patients are instructed to take 62.5 milligrams twice a day for the first month of treatment. If they respond well, the dosage amount may be doubled to 125 milligrams twice daily.

Some patients experience side effects when taking bosentan, but they are usually mild. Common side effects include temporary lightheadedness, dizzy spells, headaches, and stomach upset. Fatigue, weakness, and loss of appetite may occur as well. Rarely, bosentan has been known to cause potentially serious liver damage that can result in severe nausea and jaundice. It is essential to report any significant side effects or health concerns to the prescribing doctor so major complications can be averted.

Most people who take bosentan are able to enjoy considerable symptom relief. After a month or two of treatment, many patients are able to breathe easier and engage in higher levels of physical activity than they could before treatment began. Depending on the patient's progress, a doctor may decide to adjust dosage levels or stop treatment altogether at some point.

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