Which pulmonary arterial hypertension medication targets the nitric oxide pathway leading to vasodilation?

Riociguat is a medication specifically designed to target the nitric oxide (NO) signaling pathway, which plays a crucial role in vasodilation. It acts as a soluble guanylate cyclase (sGC) stimulant, enhancing the effects of endogenous nitric oxide. By increasing intracellular cyclic guanosine monophosphate (cGMP) levels, riociguat causes relaxation of the vascular smooth muscle, leading to vasodilation and subsequent reduction in pulmonary arterial pressure. This action is specifically beneficial in the management of pulmonary arterial hypertension (PAH), improving exercise capacity and overall hemodynamics.

The other medications listed either work through different mechanisms or do not specifically target the nitric oxide pathway. For example, macitentan is an endothelin receptor antagonist that works by blocking the effects of endothelin-1, a peptide that causes vasoconstriction. Treprostinil diolamine is a prostacyclin analog that acts primarily on the prostacyclin pathway to induce vasodilation. Selexipag is an oral selective prostacyclin receptor agonist, also working through the prostacyclin pathway. While all these medications provide therapeutic benefits in PAH, riociguat’s unique action on the nitric oxide pathway