I didn't mention it in my other reply, but this reminds me. Gabapentin (and Lyrica for that matter) also have upper dosage limits beyond which they may no longer be effective. For some, they work for a time -- even a few years -- and then just stop working entirely.

I hope you may be able to find a cause of your PN and alternative treatment. My worst symptom was the burning pain. R-lipoic acid has very effectively eliminated that for me. I still have some other kinds of pain, along with occasional cramps, shocks, needle jabs, but (for me) they're minor nuisances. The burning is gone.

There is much to learn here in the Sticky threads, archives, and asking questions. Above all there is hope and support. As I mentioned before, you're not alone in any of this.

Doc