How switching blood pressure medications affects heart and lung disease outcomes

This study is tracking what happens when people with pulmonary arterial hypertension (a serious lung condition that raises blood pressure in the lungs) switch from the medication ambrisentan to bosentan. Researchers want to understand whether this medication switch affects how well patients are doing and their overall risk of disease progression. No new drugs are being tested—the study simply follows people during their routine medical care after they've made this switch.

Doctors sometimes need to switch patients between different blood pressure medications for the lungs due to side effects, how well the medication is working, or availability. While a small amount of evidence suggests this switch is safe, researchers want to collect more detailed information from a larger group of real patients to make sure the medication change doesn't harm their health outcomes.