<unk>  is a drug that blocks endothelin, an endogenous hormone found in higher quantities in patients with pulmonary arterial hypertension. Endothelin binds to two receptors, ETA and ETB. ETA is responsible for cell growth in the vessels as well as vasoconstriction, while ETB plays a role in vasodilation, endothelin 1 clearance, and antiproliferation of cells.
Ambrisentan
Bosentan
Macitentan
Sitaxentan
Darusentan
Vericiguat
Spirapril
Nitroxinil