The following information includes only the average doses of this medicine. Do not keep outdated medicine or medicine no longer needed. This increased blood flow can cause an erection. From Mayo Clinic to your inbox Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Children 1 year of age and older weighing 45 kilograms kg or more—20 mg 3 times a day. How should this medicine be used?Dosage for erectile dysfunction 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. Brand-name Viagra is also available through Optum Store in , , mg pills starting at $80 per dose if purchased in bulk. Pros & cons Free online consultation and free shipping on medications.  · The highest recommended Viagra dose for treating erectile dysfunction (ED) is mg per day, according to the drug’s manufacturer. Doses of mg or mg would be considered off-label.