Another NonOpiate pain reliever is tapentadol. Here's the Wiki link:

http://en.wikipedia.org/wiki/Tapentadol

It's similar to tramadol in that it's dual action, both an analgesic and a norephinephrine reuptake inhibitor. It appears to be stronger than tramadol though.

I just researched it because my neurologist suggested I take it. (But I'm not going to.)