Similar values for pharmacokinetic parameters were seen in normal volunteers and in the patient population, using a population pharmacokinetic approach. Do not use this medicine if you are also using a nitrate medicine, often used to treat angina or high blood pressure. Use protective measures and ask your doctor if you have any questions about this. Ask your healthcare professional how you should dispose of any medicine you do not use. 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. Sexual activity may be a strain on your heart, especially if you have heart disease.VIAGRA is available by prescription only in 25 mg, 50 mg, and mg tablets. Patients should always ask their doctors for medical advice about adverse events. You are encouraged to report adverse events related to Viatris products by calling (U.S. only). If you prefer, you may contact the U.S. Food and Drug Administration (FDA.  · Viagra; Descriptions. Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. However the dose is usually not more than 40 mg 3 times a day. Children 1 year of age and older weighing 20 to 45 kg—20 mg 3 times a day. The recommended dosage of Viagra for erectile dysfunction (ED) is 50 mg, taken as needed about 1 hour before sexual activity. You can take it 30 minutes to 4 hours before sexual activity. And you.