There is a newer version, Nortriptoline. I have been on it for four years for fibromyalgia pain and the sleep disorder that comes with fibro. The only side effect I have experienced is constipation, which I take 2 tabs of senocot for. I have other "fibro friends" also taking it and they don't have any complaints. You may want to consider asking your doctor to switch you. Research has shown antidepressants work as the best anagesics for pain. I also have cervical prutrutions indenting my spinal cord. Another new medicine made by pfizer is Lyrica (Pregabalin) being marketed for neuropathic pain. I do not know if this is being sold in the US yet, I live in the Philippines and it has just started to be marketed here. Good Luck!