Cialis is an erectile dysfunction drug that is in the class of Cialis 50 mg drugs known as PDE5 inhibitors. The drugs in this class are the ones that inhibit the phosphodiesterase-5 enzyme. Cialis is a drug that is taken so that it can relax the muscles and improve blood movement to the penis. This is a drug that has been manufactured by experts to help in ensuring people with erectile dysfunction have got Cialis 10 mg fully erection so that they can have sexual satisfaction.