How do viagra (sildenafil) and vitamin b pills differ in appearance?

Depends!: Viagra is a brand of sildenafil. For now, it's the only version available in the states. However, there are lots of different b vitamin products. Check out www.Epocrates.Com & www.Drugs.Com. Both have a drug identification feature that will give you an idea of what viagra (and any other medication) looks like. It can also identify an unknown pill for you based upon a few clues.