PDE5 inhibitors are used to treat erectile dysfunction, pulmonary arterial hypertension, and benign prostatic hyperplasia. These medications work by blocking the enzyme phosphodiesterase type 5 (PDE5), which helps relax blood vessels and improve blood flow. Most PDE5 inhibitors are taken orally. Examples include sildenafil (Viagra, Revatio), tadalafil (Cialis, Adcirca), and vardenafil. These medications help manage your symptoms and improve your quality of life.