Riociguat is a medication used to treat pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). It works by increasing levels of nitric oxide in the body, which helps to relax blood vessels and improve blood flow. Research in this area focuses on studying the effectiveness of riociguat in treating these conditions, as well as exploring potential side effects and interactions with other medications. Additionally, researchers may be investigating new ways to improve the delivery and dosing of riociguat to maximize its benefits for patients with PAH and CTEPH.