Generic Name: Tadalafil is marketed under several brand names, including Cialis, and is used to treat pulmonary arterial hypertension, benign prostatic hyperplasia, and erectile dysfunction. Male sexual function issues, such as impotence or erectile dysfunction (ED), are treated with Cialis. Cialis helps a man achieve and maintain an erection by boosting blood flow to the penile area when combined with sexual excitement.The symptoms of benign prostatic hyperplasia, or enlarged prostate, are also treated with Cialis.