Brand names Why is this medication prescribed? If you are taking tadalafil to treat PAH or BPH, follow your doctor’s directions and the guidelines in this paragraph. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. The penis is one of the areas where this enzyme works. Tadalafil has been extensively studied for ED. Nitrates come as tablets, sublingual under the tongue tablets, sprays, patches, pastes, and ointments.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 .  · Cialis (tadalafil) is prescribed to treat erectile dysfunction and symptoms of benign prostatic hyperplasia. It comes as a tablet that’s taken as needed or once per . Cialis is a prescription medication containing the active ingredient tadalafil. Cialis belongs to a group of medications known as phosphodiesterase-5 (PDE-5) .