TREPROSTINIL treats pulmonary arterial hypertension (PAH), a condition that causes high blood pressure in the lungs. It works by relaxing your blood vessels and lowering the blood pressure in your lungs, which makes it easier for your heart to pump blood to the rest of your body. It can also help you breathe easier and be more active. Get Tyvaso Dpi for as low as $24,267.89, save up to 80% off the average retail price for the most common version, by using a GoodRx coupon.