Clinical Pharmacology of Endothelin Receptor Antagonists Used in the Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a devastating life-threatening disorder characterized by elevated pulmonary vascular resistance leading to elevated pulmonary arterial pressures, right ventricular failure, and ultimately death. Vascular endothelial cells mainly produce and secrete endothelin (ET-1) in vessels that lead to a potent and long-lasting vasoconstrictive effect in pulmonary arterial smooth muscle cells. Along with its strong vasoconstrictive action, ET-1 can promote smooth muscle cell proliferation. Thus, ET-1 blockers have attracted attention as an antihypertensive drug, and the ET-1 signaling system has paved a new therapeutic avenue for the treatment of PAH. We outline the current understanding of not only the pathogenic role played by ET-1 signaling systems in the pathogenesis of PH but also the clinical pharmacology of endothelin receptor antagonists (ERA) used in the treatment of PAH.