Xanax 2mg bars (alprazolam) are a high-dose prescription benzodiazepine used to treat anxiety and panic disorders. These bars are rectangular tablets that contain 2mg of alprazolam, designed to be broken into smaller doses if needed. Xanax works by enhancing the effects of gamma-aminobutyric acid (GABA), a neurotransmitter that slows brain activity, producing a calming and sedative effect.