<unk>  is a small molecule that blocks the action of endothelin (ET) on the endothelin-A (ETA) receptor selectively (by a factor of 6000 compared with the ETB). It is a sulfonamide class endothelin receptor antagonist (ERA) and is undergoing Food and Drug Administration (FDA) review for treating pulmonary hypertension. The rationale for benefit compared with bosentan, a nonselective ET blocker, is negligible inhibition of the beneficial effects of ETB stimulation, such as nitric oxide production and clearance of ET from circulation. In clinical trials, the efficacy of<unk>  has been much the same as bosentan, but the hepatotoxicity of<unk>  outweighs its benefits. Dosing is once daily, as opposed to twice daily for bosentan.
Sitaxentan
Bosentan
Macitentan
Ambrisentan
Darusentan
Vericiguat
Tafamidis
Riociguat