There are many other treatments for erectile dysfunction. Remember that expediting will cost extra. Always take Viagra under the supervision of a licensed medical professional, who can properly monitor your dose and any side effects. If you do, you may save money with online pharmacies that accept yours. This site is intended only for U. · Take sildenafil exactly as it was prescribed for you. Follow all directions on your prescription label and read all medication guides or instruction sheets. Revatio is usually taken three times each day, about 4 to 6 hours apart. Viagra is usually taken only when needed, 30 minutes to 1 hour before sexual activity. Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil (Viagra) by mouth, about 1 hour before sex, as needed. The maximum recommended dose is mg. Don’t take sildenafil (Viagra) more than once daily (at any dose). Written by Brian Leonard, PharmD, BCACP, BCGP. You shouldn’t take Viagra or medications like it without a prescription. It’s risky due to side effects, possible contaminants in illegal pills, and the risk of developing ED. Some .