Viagra (sildenafil citrate) is a breakthrough treatment for male erectile dysfunction or ED, often called impotence. It is a convenient, discreet pill you take only when you want to have sex. Viagra can help many men who have ED get and keep an erection when they become sexually stimulated, either physically or visually. So with Viagra, a touch or a glance from your partner can again lead to something more. Viagra comes in 50 mg and 100 mg tablets produced by Pfizer Inc.