Riociguat is a potent, oral stimulator of soluble guanylate cyclase (sGC). It is the first member of a novel class of compounds, being developed by Bayer as an investigational, oral treatment to target a key molecular mechanism underlying pulmonary hypertension (PH). Riociguat demonstrated robust clinical efficacy in two separate PH indications: chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension(PAH). Riociguat works in two ways: it sensitizes sGC to endogenous NO by stabilizing the NO-sGC binding and directly stimulates sGC via a different binding site, independently of NO. Riociguat stimulates the NO-sGC-cGMP pathway and leads to increased generation of cGMP with subsequent vasodilation. Through this unique way of working, riociguat decreases blood pressure within the pulmonary arteries that take blood from the heart to the lungs, reducing pressure on the heart leading to improved patient outcomes.