Selexipag blood pressure drug molecule. Computer illustration showing the structure of a molecule of the prostacyclin receptor agonist drug selexipag. Selexipag is used to treat pulmonary arterial hypertension (PAH) - high blood pressure (hypertension) in the pulmonary artery, pulmonary veins, or pulmonary capillaries. Atoms are represented as colour-coded spheres: carbon (grey), hydrogen (white), nitrogen (blue), oxygen (red), sulphur (yellow).