medication used to treat erectile dysfunction. It works by increasing blood flow to the penis when aroused, allowing a man to get and maintain an erection. It can also be used to treat benign prostatic hyperplasia (enlargement of the prostate). Introduction Cialis is a medication used to treat erectile dysfunction and other symptoms of male sexual dysfunction. It is a member of the family of drugs known as phosphodiesterase type 5 (PDE5) inhibitors, which work by blocking an enzyme in the body that is responsible for regulating blood flow to the penis. By inhibiting this enzyme, Cialis increases the levels of nitric oxide in the body, which relaxes the smooth muscles in the penis and increases blood flow, resulting in an erection Cialis is a prescription medication used to treat erectile dysfunction (ED) and other symptoms of male sexual dysfunction. It belongs to a family of drugs known as phosphodiesterase type 5 (PDE5) inhibitors, which work by blocking an enzyme in the body that is responsible for regulating blood flow to the penis. By inhibiting this enzyme, Cialis increases the levels of nitric oxide in the body, which relaxes the smooth muscles in the penis and increases blood flow, resulting in an erection.