Bleeding disorders, history of or Stomach ulcer, or history of or—Chance of problems occurring may be increased. What sites do you recommend? The effects may be increased because of slower removal of the medicine from the body. Your doctor will answer each of your questions and tell you whether or not you need to talk to the urologist, who is a specialist in dealing with such issues. For treatment of erectile dysfunction: For oral dosage form tablets : Adults up to 65 years of age—50 milligrams mg as a single dose no more than once a day, 1 hour before sexual intercourse.If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in adult males* with ED. With ED, you .  · Use only the brand of this medicine that your doctor prescribed. Different brands may not work the same way. Dosing. If you take sildenafil for pulmonary . Depending on your particular health concerns, you might go directly to a specialist — such as a doctor who specializes in male genital problems (urologist) or a .