If you experience chest pain, dizziness, or nausea during sex, seek immediate medical help. This site is intended only for U. Sudden vision loss in one or both eyes can be a sign of a serious eye problem called non-arteritic anterior ischemic optic neuropathy NAION. Sildenafil is also used in both men and women to treat the symptoms of pulmonary arterial hypertension. Some people may also have ringing in their ears tinnitus or dizziness. Do not use more of it and do not use it more often than your doctor ordered.The normal dose when starting Viagra is 50 mg, as needed. The maximum dose of Viagra is mg each day. Doses above the maximum dose, such as mg . 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 .  · Viagra; Descriptions. Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines .