What kind of workup have you had for your injury?? MRI?? Nerve conduction studies?? Sounds like you have been tried on the proper medications for neuropathic pain/sciatica. Lots of times meds are done on a trial and error basis to see what works best for you.

Addiction is a psychological condition and must be differentiated from tolerance to narcotic medications. Most everyone will develop a tolerance to narcotics, meaning you need higher and higher doses to achieve the same effect.