Xanax is a patent prescription medication used to treat anxiety and panic disorders. Xanax is the brand name for Alprazolam, a benzodiazepine medication that enhances the effects of a naturally occurring chemical in the brain and creates a calming effect in the body. Depending on the severity of the disorder, Xanax bars are available in a variety of doses. Doses range from 0.25mg to 3mg.