Sally,
I tried Cymbalta in 2005. I took it for 10 months. I was on Neurontin and Vicodin when I started Cymbalta. My neuro told me it was new and could be great for my PN, and I might be able to go off the Neurontin (I was up to 3600mg per day).
Cymbalta did help my pain, and I thought it was great at first. Within a few months, however, it seemed to quit working and the side effects of horrible constipation, night after night of insomnia, mood swings, weight gain (especially in the belly), high blood pressure, escalating cholesteral, to name the worst of them. It became a nightmare for me.
I ended up going back to Neurontin, Vicodin, and more research on my own as to what might be the cause of my PN. Sadly, the Cymbalta adventure led to me and my neuro parting ways. I came off Cymbalta fast, which I later found out was wrong. The withdrawal was terrible. I am still not sure I have recovered from the effects of Cymbalta. I personally could not recommend it to anyone. I can only suggest you think about it real hard, and proceed with caution.
I have found more help from reading this forum, and trusting in the knowledge of those here who understand and suffer with us. I have reduced my Neurontin now by half after eliminating gluten from my diet, and I take other supplements recommend here along with extra B12. I watch my stress which also seems to affect my pain level.
I tried Lyrica with my new neuro, but it did not help me. Neurontin seems to be safest for me. I hope my experience is of help to you and others.
Wishing the best for you.
Mrs. Schumacher