Bosentan blocks endothelin, a substance that tightens blood vessels. By relaxing the arteries in the lungs it lowers the pressure the right side of the heart has to pump against, which improves breathlessness and exercise capacity.

What Bosentan Is Used For

Pulmonary arterial hypertension
Reducing new digital ulcers in systemic sclerosis
Improving exercise tolerance in selected patients

Common Side Effects

Headache and flushing
Abnormal liver tests
Ankle swelling
Anaemia and tiredness

Precautions

Monthly liver blood tests are mandatory throughout treatment, and haemoglobin is checked as well. Bosentan causes serious harm to an unborn baby, so pregnancy must be excluded before starting and reliable contraception used, noting that it reduces the effectiveness of hormonal contraceptives. Never stop it abruptly, and report yellowing of the eyes, dark urine, nausea or unusual tiredness.

This page is general information only. It is not a substitute for advice from your doctor or pharmacist, and it does not include dosage. Always follow the directions given to you and read the leaflet inside the pack.