NCIt definition : An orally bioavailable, selective antagonist of the endothelin type-A (ETA) receptor
that may be used for the treatment of pulmonary arterial hypertension (PAH). Upon
administration, ambrisentan targets and binds to ETA receptor, which prevents the
binding of endothelin-1 (ET-1) to the ETA receptor and ET-1/ETA-mediated vasoconstriction
and cell proliferation. This may lead to vasodilation. ET-1 concentrations are increased
in plasma as well as lung tissue in PAH, and ET-1 may play a key role in the pathogenesis
of PAH.;