Capsaicin
"Been using 4% lidocaine (along with gabapentin, which has yet to do anything after a week) and ibuprofen for my postherpetic neuralgia.  Asked Dr for prescription strength lidocaine cream and he recommended OTC Capsaicin.  He recommened zostric, but the Capszin-HP was on sale (.01%) so I got that.  Applied first time. Felt like my skin was on FIRE!!!  MUCH worse than the neuralgia pain. And it lasted almost an hour, leaving me in worse pain than before I applied.  Will never use this again."