I'm on 0.5 mg Xanax XR; I take one pill in the morning and the other at night, before bed. That is a total of one mg a day. How long after taking it does it take to get into your system, and how long does it stay in your system? After how long do its effects start to wear off, and one needs another one? Is 0.5 Xanax XR a suitable dose for generalized anxiety disorder? I've been on it for years and now I'm kind of curious about some stuff.