Do not use this medicine if you are also using a nitrate medicine, often used to treat angina or high blood pressure. Patients should always ask their doctors for medical advice about adverse events. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine. Children—Use is not recommended. Age greater than 50 years or Coronary artery disease or Crowded disc or low cup to disc ratio in the eye an eye disorder or Diabetes or Hyperlipidemia high fats in the blood or Hypertension high blood pressure or Non-arteritic anterior ischemic optic neuropathy or NAION serious eye condition , history of or Smoking—May increase the chance for a serious side effect in the eye called NAION.VIAGRA is available by prescription only in 25 mg, 50 mg, and mg tablets. Not actual size. TIPS FOR TAKING VIAGRA. Take VIAGRA exactly as your doctor tells you to . Revatio Viagra Descriptions Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines called . FAQs What to consider Cost Overdose Ask your doctor Q&A Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. .