Xanax is not intended for prolonged use, and doctors typically prescribe it for the shortest duration necessary. It is uncertain whether using Xanax for more than 4 months for Generalized Anxiety Disorder (GAD) or more than 10 weeks for panic disorder is safe or effective. When you and your doctor decide to discontinue Xanax, your doctor will gradually reduce your dosage to minimize the risk of withdrawal symptoms that may occur if you abruptly stop the treatment.