List of products in the National Drug Code with proprietary name . Selexipag is used to treat high blood pressure in the lungs (pulmonary arterial hypertension-PAH). It is used to help slow down worsening of PAH and to decrease the chance of needing treatment in a hospital. Selexipag works by making it easier for blood to flow through the arteries in your lungs. This effect helps increase your ability to exercise.