I was on Zyprexa for quite some time a few years back, I gained 30 pounds from this drug. All these meds have risk of withdrawls. Always. Everyone is different and may experience, less, more or none at all. The most important thing is to do exactly what your doctor says, no matter what. Sometimes even weaning you still may experience some withdrawls, but the idea is to go off slowly so the withdrawls aren't as bad. Drink lots of water and get up slowly when laying down. Take it easy, eat and drink water regularly.
All the best,
Bipolar II, Anxiety/Panic Disorder
--currently not on meds for bp--