Seems like so many people respond to different drungs in different ways. The Cymbalta made me incredibly sleepy and woke me up in the middle of the night (go figure) and did nothing for my pain. Tricyclics made me completely zombie-like, I was so tired, and they didn't help with the pain. I have a prescription for cyclobenzaprine which helps with the pain, but completely knocks me out, so I only take it when the pain's really bad.
Darn near every drug makes me drowsy, though, so me saying that things make me sleepy probably doesn't mean a whole lot.