Cialis is used to treat erectile dysfunction (impotence) in men. Adcirca, another brand of tadalafil, is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women. Cialis (tadalafil) relaxes muscles and increases blood flow to particular areas of the body.
        Cialis can decrease blood flow to the optic nerve of the eye, causing sudden vision loss. This has occurred in a small number of people taking Cialis, most of whom also had heart disease, diabetes, high blood pressure, high cholesterol, or certain pre-existing eye problems, and in those who smoke or are over 50 years old. It is not clear whether Cialis is the actual cause of vision loss.
         If you have any of these other conditions, you may need a Cialis dose adjustment or special tests:

• heart disease or heart rhythm problems;
• a recent heart attack .
• a recent history  of a stroke, or congestive heart failure;
• angina (chest pain), high or low blood pressure;
• liver disease;
• kidney disease (or if you are on dialysis);
• a blood cell disorder such as sickle cell anemia.
• a bleeding disorder such as hemophilia;
• a stomach ulcer;
• retinitis pigmentosa.
• a physical deformity of the penis (such as Peyronie's disease); or
• if you have been told you should not have sexual intercourse for health reasons.