I have been on Nucynta 3 months. At first I thought I had found my answer for my pain.I have severe chronic pain due to spinal stenosis, bulging disc, and I need a total knee replacement. I've taken sleeping meds for years & what I'm on & the Nucynta was working fine. My knee eased up to the point I wasn't going to have surgery. I went to the clinic & all was fine. But a week or so went by & all of a sudden I couldn't sleep, my body was shaking I was having panic attacks. I couldn't eat, I've lost ten pounds at least I feel horrible all over.My pain went from about a 5 to over a 10 level. I'm not getting any more than four hours of sleep now. I was also put on Dexilant 60 mg for my stomach. I looked it up & there wasn't any thing to indicate the two meds would interfere with my sleep or any thing else. I need to know if the Nucynta worked so great for three months can it just all of a sudden keep me from sleeping & have this kind of reaction. I don't think my doctor will believe me because I told her how I good it worked & how I felt better & then bam my body fell apart.