I, too, after Viagra switched to Cialis. And this is on the advice of the doctor. Viagra gave an "explosive" effect, my blood pressure increased, and my state of health was not very good. The doctor said that Cialis acts "softer" and recommended it. And yes, it turned out. Now I take Cialis, but not constantly, and if necessary. In general, I would say once again that it is better to choose the drug together with a doctor, since what suits a friend will not necessarily work for you.