Interestingly, Cialis has been more linked to improved self-esteem and other psychological factors than the other PDE5 medications. How Effective Is Cialis? A small number of patients taking Cialis also reported abnormal vision. Also tell your doctor if you or any of your family members have or have ever had an eye disease such as retinitis pigmentosa an inherited eye condition that causes loss of vision or if you have ever had sudden severe vision loss, especially if you were told that the vision loss was caused by a blockage of blood flow to the nerves that help you see. The as-needed dose is usually 10 mg but can range from 5—20 mg.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 prostate) which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency in adult men. Tadalafil is a generic version of the prescription drug Cialis. Doctors prescribe it to treat erectile dysfunction and benign prostatic hyperplasia. It helps relieve erectile dysfunction by.  · Cialis is available only by prescription. It’s not available over the counter.