Xanax is the brand name for alprazolam, it iis a benzodiazepine that doctors prescribe to treat generalized anxiety disorder and panic attacks. Xanax is one of the most commonly prescribed anti-anxiety medications in the world. Xanax is a Schedule IV controlled substance in the United States. Xanax can help many people feel calm in stressful situations; it also has the potential for side effects, overdose, and dependence. A "bar" is one of the most commonly used forms of Xanax.