I've been posting about this on and off all year trying to get some answers.
Anyway, I'll keep it short.
I've been unable to tolerate Trimethoprim or Doxycycline without the both causing unbearable neuropathic pain (burning, stinging, tingling, etc). I tried multiple times and failed to continue after 2-3 days. I've had a chronic UTI for a year now.
After experimenting a lot, I figured out that by taking R-Alpha Lipoic Acid (stabalized ALA supplements) I was able to completely prevent the neuropathic pain when taking high dose Trimethoprim. I take it at the same time as the antibiotic, as peak concentrations of both occur about the same time
I reall hope that helps someone!
I had tried the combiation of Benfotiamine, B12, methyl folate, NAC, and ALCAR prior to R-ALA but it did not prevent the neuropathic pain with antibiotics or Hiprex. I am still taking all those, but the addition of R ALA is what completely prevented the severe nerve pain flare up with Trimethoprim.
Been on the antibiotic now for over 2 weeks. No problems!