BOGO 50% off select Walgreens health & wellness. Menu. Sign in Create an account. Find a Store. Prescriptions. Back. Prescriptions.What side effects can this medication cause? Children 1 year of age and older weighing 20 to 45 kg—20 mg 3 times a day. Tell your doctor if any of these symptoms are severe or do not go away: headache. You may take this medicine with or without food. Different brands may not work the same way.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. How much does sildenafil citrate or viagra cost near you? Find the best sildenafil citrate or viagra prices near you now with our cost comparison tool and start saving today. Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in is also used to treat pulmonary arterial hypertension, a serious heart and lung drug is more popular than comparable drugs. It is available in generic and brand versions. Generic sildenafil is covered by most Medicare and insurance plans, but .Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine. Before taking sildenafil, tell your doctor and pharmacist if you are allergic to sildenafil, any other medications, or any of the ingredients in sildenafil tablet or suspension. If you need emergency medical care for a heart problem, it is important that your doctor knows when you last took sildenafil. If you will be taking this medicine for pulmonary arterial hypertension, your doctor will want to check your progress at regular visits. Ask your doctor if you have any questions. However, if you take sildenafil with a high-fat meal, it will take longer for the medication to start to work. If it is not treated right away, priapism can permanently damage your penis sudden vision loss in one or both eyes.