Which medication is an oral prostanoid used for pulmonary arterial hypertension?

Treprostinil diolamine is indeed an oral prostanoid indicated for the treatment of pulmonary arterial hypertension (PAH). It is a derivative of prostacyclin, which serves to dilate pulmonary and systemic arterial vascular beds, as well as to inhibit platelet aggregation. This mechanism helps improve exercise capacity and symptoms in patients with PAH.

While other medications mentioned might be related to pulmonary arterial hypertension, they have different mechanisms of action or formulations. Macitentan is an endothelin receptor antagonist that is effective for PAH but is not a prostanoid. Riociguat is a soluble guanylate cyclase stimulator that enhances the effects of nitric oxide, also not classified as a prostanoid. Iloprost, while a prostanoid, is administered via inhalation and not orally. In contrast, treprostinil diolamine being available in an oral formulation uniquely positions it for patients who may require oral therapy for the long-term management of PAH. Thus, treprostinil diolamine represents an important option in the therapeutic landscape of PAH.