Without physical action to the penis, such as that occurring during sexual intercourse, tadalafil will not work to cause an erection. Benign prostatic hypertrophy is a condition in which the prostate gland becomes enlarged, obstructing the free flow of urine. For this purpose, one dose works for up to 72 hours. Cialis is also highly effective in reducing the symptoms of BPH. Tadalafil works on the PDE5 enzyme in the lungs to relax the blood vessels.Cialis (tadalafil) is a brand-name prescription medication. The Food and Drug Administration (FDA) has approved it for use in adult males.* It’s approved to: treat erectile dysfunction (ED). We have good news for you: generic Cialis, used to treat erectile dysfunction (ED)and enlarged prostates, just hit pharmacies. Prices for the generic, known as tadalafil, are more than 50% less than those of brand-name Cialis. As more men are able to afford tadalafil and treat their ED, it’s likely that many will have questions. Generic name: tadalafil [ ta-DAL-a-fil ] Brand names: Adcirca, Cialis Drug class: Impotence agents Medically reviewed by Sanjai Sinha, MD. Last updated on Uses Warnings Before taking Dosage Side effects Interactions FAQ What is Cialis?