List of products in the National Drug Code with proprietary name . Riociguat is used to treat high blood pressure in the lungs (pulmonary hypertension). It can also be used to treat a certain type of high blood pressure in the lungs caused by blood clots (chronic thromboembolic pulmonary hypertension) when surgery has not been fully successful or is impossible. Riociguat works by relaxing and widening the blood vessels in your lungs so blood can flow more easily. Decreasing high blood pressure in the lungs allows your heart and lungs to work better and improves your ability to exercise.