Since vardenafil is used as needed, you are not likely to be on a dosing schedule. Grapefruit and Seville oranges may interact with vardenafil and cause side effects. Call your doctor for medical advice about side effects. Different brands may not work the same way. If you receive medical care for heart problems, tell your caregivers when you last took vardenafil. Use the medicine exactly as directed. This medicine does not prevent the spread of sexually transmitted diseases such as human immunodeficiency virus HIV. · Adults up to 65 years—10 mg as a single dose, no more than once per day, approximately 1 hour before sexual activity. Your doctor may adjust your dose if needed. . Hearing loss or ringing in ears. Heart attack—pain or tightness in the chest, shoulders, arms, or jaw, nausea, shortness of breath, cold or clammy skin, feeling faint or lightheaded. . 5 milligrams 10 milligrams 20 milligrams The best dose depends on your: age health medications Dosages Levitra is available as an oral tablet in several strengths. .