Do not start these medications while taking sildenafil without discussing it with your healthcare provider. Shake the liquid well for 10 seconds before each use to mix the medication evenly. Viagra vs. These medicines all work well for ED. It might work longer if you have mild to moderate erectile dysfunction. The medication was developed by U. Clinically proven to help you get an erection when you need it.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 . Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Sildenafil (Viagra). This medicine works best when you take it on an empty stomach an hour before sex. The body takes longer to absorb it after a high-fat meal or .