It works to treat erectile dysfunction by increasing blood flow to the penis during sexual stimulation. They’re often the first line of treatment for trouble getting or keeping an erection, called erectile dysfunction ED. Your doctor may need to change the doses of your medications or monitor you carefully for side effects. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail. An inherited eye disease that affects the retina. What special precautions should I follow?Cialis is a medication approved by the Food and Drug Administration (FDA) often used to treat erectile dysfunction (ED) and benign prostatic hyperplasia (BPH) in . Oral medicines for ED usually work well and cause few side effects. The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil . 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 .