ED occurs more frequently in older men. Cialis will be available by prescription only. When you make the appointment, be sure to ask if there’s anything you need to do in advance. Your doctor can help you to choose the dosage that works for your current physical needs and past medical history. Side effects Side effects of oral ED medicines are often mild. Sorry something went wrong with your subscription Please, try again in a couple of minutes Retry Clinical trials Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this condition. Cialis is a brand-name prescription medication.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 .  · 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 . 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 .