If too much is used, the chance of side effects is increased. They have the same benefits and risks as their brand-name counterparts. This condition may require prompt medical treatment to prevent serious and permanent damage to your penis. Cialis tadalafil : This ED medication works with the same principle as Viagra, but lasts up to 36 hours. You may take this medicine with or without food. Refills: See if you can set up automatic refills or order as needed.Compare sildenafil prices, print discount coupons, find manufacturer promotions, copay cards and patient assistance programs. Brand names for sildenafil include Viagra, Revatio, 10 mg/mL sildenafil oral powder for reconstitution. from $7, for milliliters. Quantity Per unit Price; milliliters. 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. If you have these symptoms, stop taking VIAGRA and contact a doctor right away. have or have had heart problems such as a heart attack, irregular heartbeat, angina, chest pain, narrowing of the aortic valve, or heart failure. have low blood pressure, or high blood pressure that is not controlled.