20.3 : 肺动脉高压的治疗：内皮素受体拮抗剂

Endothelin receptor antagonists or ERAs counteract the effects of endothelins, or ETs, to treat pulmonary arterial hypertension or PAH.

ETs are produced through a sequence of steps involving endothelin-converting enzyme or ECE.

ECE-1, in particular, is the rate-limiting step in synthesizing ET-1, the predominant form of endothelin.

ET-1 interacts with receptors, ET_A, and ET_B and triggers both vasoconstriction and vasodilation in the pulmonary arteries.

Currently, three oral ERAs are available for PAH treatment.

Bosentan and macitentan block both ET_A and ET_B receptors, effectively reducing PAH progression and symptoms, while ambrisentan selectively inhibits ET_A.

Common side effects of these drugs include headache, pulmonary edema, nasal congestion, and pharyngitis.

These drugs may elevate liver transaminases, rendering them unsuitable for patients with moderate-to-severe liver disease.

Importantly, due to potential harm to fetuses, endothelin antagonists must be avoided during pregnancy.