Capsaicin Tested On Surgical Wounds

Ponca City, We Love You writes "Bite a hot pepper, and after the burn your tongue goes numb. The Baltimore Sun reports that Capsaicin, the chemical that gives chili peppers their fire, is being dripped directly into open wounds during highly painful operations, bathing surgically exposed nerves in a high enough dose to numb them for weeks. As a result patients suffer less pain and require fewer narcotic painkillers as they heal. 'We wanted to exploit this numbness,' says Dr. Eske Aasvang, a pain specialist who is testing the substance. Capsaicin works by binding to C fibers called TRPV1, the nerve endings responsible for long-lasting aching and throbbing pain. Experiments are under way involving several hundred patients undergoing various surgeries, including knee and hip replacements using an ultra-purified version of Capsaicin to avoid infection. Volunteers are under anesthesia so they don't feel the initial burn."

Comments

Anesthesia notes

[neapolitan]

Very interesting. I can say as a doctor I've never seen this used before though, but it reminded me of a few things:

During surgery the patient is unconscious, and thus feels no pain, but good surgeons recognize that local anesthesia is still necessary. It's a bit counterintuitive, and I remember being puzzled back in medical school that the surgeons would still numb the area before doing any work despite the patient being unresponsive regardless. The thought is that nerves are damaged and there are changes / responses to the painful stimulus that persist despite the individual being unconscious; in a way, you still have neuronal pain signals if you don't give local anesthesia. It also prevents the patient from waking up with pain in the operative site before you can give other types of painkillers.

Lidocaine (and capsaicin to some degree) would prevent the nerves from ever signaling -- they block the sodium channel that is necessary for nerves to fire. No firing -- no pain, *and* no no neuronal changes, and hopefully no long term pain. Lidocaine wears off after 2 hours or so, while it seems that capsaicin has much longer densitization effects.

Of note, capsaicin is also used in "pepper spray" self-defense products advertised to women in particular. I wonder if one could become numb to this after repeated sprayings. Hmmm, anybody on slashdot may be able to answer this from experience? :)