... I just switched from xanax .5 3x a day to xanax xr 2x a day (.5). I have only been on xanax for a few weeks but was havings problems between dosage so i switched to XR. The xr .5 is working great for panic during the day but when it wears off (in the morning and night) I get tremors really bad, hand shaking, racing heart, etc... I read something about rebound anxiety and think this is what's going on. This is only day 3 on the new XR. Will this side effect go away after I've been on it awhile. If not, I guess I think I'm goign to have to stop taking it and go back to the regular. Thanks for any help.