We have used it a lot - mostly off label.
In my experience, it works great for allodynia, but not for neuropathic pain without allodynia (like post thoracotomy pain).
Why wouldn't it work? There are a billion studies showing that capsaicin works - there is no question there. But what is the problem? It is rare to find a patient that will actually use that crap. The advantage to Qutenza is you get all the benefit from capsaicin in a 1 hr treatment and supposedly it should last 3 months.
We have had some PHN patients get 3 months. I don't see much HIV patients, but I have heard it works well with their peripheral neuropathy.
Most tolerate it well. The studies show that it is the last 10 minutes of treatment that was the most uncomfortable.
Dr Wallace (UCSD) , who did a lot of the studies, told us he pretreats with some valium and percocet, and that almost everyone does great with that. He doesn't use EMLA.
When I use it peripherally, I do a nerve block first - then leave it on for 90 minutes instead of the recommended 60 minutes.
I used it on a guy with horrible allodynia from CRPS in his foot - and it got rid of the allodynia for a long time. he still had a lot of pain in the foot though.