What is 3mg Xanax XR used for? 3mg Xanax XR is an incredibly potent benzodiazepine commonly used to treat GAD (or generalized anxiety disorder), panic disorders, insomnia, and many other anxiety disorders. Xanax is a powerful medication with temporary as well as long-term effects. While Xanax can help treat the previously mentioned disorders, doctors must … Continue reading How long does it take for 3mg Xanax XR to start working?