I was on it 7 weeks for back pain. I am weaning slowly, but I may be going to fast even at that. I cut back by an 1/8 pill yesterday & last nite I had muscle spasms & headache. Medicines affect me differently, plus I'm on klonopin & trazadone for dep. so that is complicating the w/d I think, as both those meds were listed as not to be given with ultracet. Each time I cut back, I have the reactions.