Ask your healthcare professional how you should dispose of any medicine you do not use. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail. How should this medicine be used? Do not keep outdated medicine or medicine no longer needed. It’s nothing to feel embarrassed about. The amount of a dosage varies based on the strength of your dose, how much you may take in a day, and how often you may take it.Last updated on Uses Warnings Before taking Dosage Side effects Interactions FAQ What is sildenafil? Sildenafil relaxes muscles of the blood vessels and . 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 .  · 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. .