NCIt definition : A sulfonamide-derived, competitive and specific endothelin receptor antagonist with
a slightly higher affinity for the endothelin A receptor than endothelin B receptor.
Bosentan blocks the action of endothelin 1, an extremely potent endogenous vasoconstrictor
and bronchoconstrictor, by binding to endothelin A and endothelin B receptors in the
endothelium and vascular smooth muscle. Bosentan decreases both pulmonary and systemic
vascular resistance and is particularly used in the treatment of pulmonary arterial
hypertension.;