I have idiopathic SFN. No numbness, but lots of burning pain in my toes, plus pain and tenderness pretty much everywhere. Two years ago I switched from pregabalin (Lyrica) to carbamazepine (Tegretol), which I had been on previously for seizures. The relief was immediate. However I immediately started gaining weight - 10 pounds in the first two months, then it continued. I’ll admit I gave up on weight loss and just ate whatever I wanted, once I realized the Tegretol was making weight loss very discouraging.
I switched to lamotrigine (Lamictal) about 2 1/2 months ago. Ouch!!! The burning toes returned within 48 hours of starting to wean off Tergretol. This has been a rough period, with lots of neuropathy pain.
Yesterday I started another drug, oxcarbazepine (Trileptac). It is similar to Tegretol, but hopefully without weight gain. Even at a low starting dose, I felt immediate relief from the burning pain. Yesterday after just two doses of 150mg, I urinated so much that I felt lighter. I was also very sleepy all day, but I can take that short term.