Tadalafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow more easily. Sorry something went wrong with your subscription Please, try again in a couple of minutes Retry. This medicine is also used to treat erectile dysfunction and signs and symptoms of BPH. Cialis Tadalafil is one of the most popular erectile dysfunction medications available today. Tadalafil comes as a tablet to take by mouth. Also tell your doctor if you have or have ever had pulmonary veno-occlusive disease PVOD; blockage of veins in the lungs ; any condition that affects the shape of the penis; diabetes; high cholesterol; high or low blood pressure; irregular heartbeat; a heart attack or heart failure; angina chest pain ; a stroke; ulcers in the stomach; a bleeding disorder; blood circulation problems; blood cell problems such as sickle cell anemia a disease of the red blood cells , multiple myeloma cancer of the plasma cells , or leukemia cancer of the white blood cells ; or heart, kidney, or liver disease.Cialis is a prescription drug used to treat erectile dysfunction and benign prostatic hyperplasia. Learn how to lower long-term drug costs and more.  · Tadalafil works on the PDE5 enzyme in the lungs to relax the blood vessels. This will increase the supply of blood to the lungs and reduce the workload of the heart. . Tadalafil (Cialis) is used to treat erectile dysfunction (ED, impotence; inability to get or keep an erection), and the symptoms of benign prostatic hyperplasia (BPH; an enlarged .