· For oral dosage forms (suspension or tablets): Adults—20 milligrams (mg) 3 times a day. Your doctor may adjust your dose as needed and tolerated. .This medication is taken with or without food an hour before sex. Often, these are prescribed for chest pain called angina. Take sildenafil at around the same times every day. Sorry something went wrong with your subscription Please, try again in a couple of minutes Retry. If you become pregnant while taking sildenafil, call your doctor. Sildenafil comes as a tablet and suspension liquid to take by mouth. Take sildenafil as needed before sexual activity.Last updated on Uses Warnings Before taking Dosage Side effects Interactions FAQ What is sildenafil? Sildenafil relaxes muscles of the blood vessels and . Take sildenafil as needed before sexual activity. The best time to take sildenafil is about 1 hour before sexual activity, but you can take the medication any time from 4 hours to 30 . Overdose Ask your doctor Q&A Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a .You can take this medicine with or without food 30 minutes before sex, depending on the dose. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. Children 1 year of age and older weighing 45 kilograms kg or more—20 mg 3 times a day. When choosing one, tell your doctor or other health care professional what your preferences are, such as cost, ease of use, how long the drug’s effects last and side effects. Children 1 year of age and older weighing 20 to 45 kg—20 mg 3 times a day. Side effects Side effects of oral ED medicines are often mild.