egads!  this scares me!  i sure hope they inform the patient first and ask
permission before doing this kind of thing during surgery!  my sister and a
close friend of mine have horrible reactions to capsaicin.  one gets huge
blisters from the slightest contact and the other can't touch it either,
because  it causes leisions, literally eats holes in her skin.

kate

Scientists Conduct Test to See if Chemical in Hot Sauce May Also Numb
Surgery Pain
Monday, October 29, 2007    14:36 PDT

WASHINGTON, D.C.  --  Devil's Revenge. Spontaneous Combustion. Hot sauces
have names like that for a reason. Now scientists are testing if the stuff
that makes the sauces so savage can tame the pain of surgery.

Doctors are dripping the chemical that gives chili peppers their fire
directly into open wounds during knee replacement and a few other highly
painful operations.

Don't try this at home: These experiments use an ultra-purified version of
capsaicin to avoid infection _ and the volunteers are under anesthesia so
they don't scream at the initial burn.

How could something searing possibly soothe? Bite a hot pepper, and after
the burn your tongue goes numb. The hope is that bathing surgically exposed
nerves in a high enough dose will numb them for weeks, so that patients
suffer less pain and require fewer narcotic painkillers as they heal.

"We wanted to exploit this numbness," is how Dr. Eske Aasvang, a pain
specialist in Denmark who is testing the substance, puts it.

Chili peppers have been part of folk remedy for centuries, and heat-inducing
capsaicin creams are a drugstore staple for aching muscles. But today the
spice is hot because of research showing capsaicin targets key pain-sensing
cells in a unique way.

California-based Anesiva Inc.'s operating-room experiments aren't the only
attempt to harness that burn for more focused pain relief. Harvard
University researchers are mixing capsaicin with another anesthetic in hopes
of developing epidurals that wouldn't confine women to bed during
childbirth, or dental injections that don't numb the whole mouth.

And at the National Institutes of Health, scientists hope early next year to
begin testing in advanced cancer patients a capsaicin cousin that is 1,000
times more potent, to see if it can zap their intractable pain.

Nerve cells that sense a type of long-term throbbing pain bear a receptor,
or gate, called TRPV1. Capsaicin binds to that receptor and opens it to
enter only those pain fibers _ and not other nerves responsible for other
kinds of pain or other functions such as movement.

These so-called C neurons also sense heat; thus capsaicin's burn. But when
TRPV1 opens, it lets extra calcium inside the cells until the nerves become
overloaded and shut down. That's the numbness.

"It just required a new outlook about ... stimulation of this receptor" to
turn those cellular discoveries into a therapy hunt, says NIH's Dr. Michael
Iadarola.

Enter Anesiva's specially purified capsaicin, called Adlea. Experiments are
under way involving several hundred patients undergoing various surgeries,
including knee and hip replacements. Surgeons drip either Adlea or a dummy
solution into the cut muscle and tissue and wait five minutes for it to soak
in before stitching up the wound.

Among early results: In a test of 41 men undergoing open hernia repair,
capsaicin recipients reported significantly less pain in the first three
days after surgery, Aasvang reported this month at a meeting of the American
Society of Anesthesiologists.

In a pilot U.S. study of 50 knee replacements, the half treated with
capsaicin used less morphine in the 48 hours after surgery and reported less
pain for two weeks. Ongoing studies are testing larger doses in more
patients to see if the effect is real.

There's a huge need for better surgical pain relief, says Dr. Eugene
Viscusi, director of acute pain management at Thomas Jefferson University in
Philadelphia, one of the test sites. Morphine and its relatives, so-called
opioid painkillers, are surgery's standby. While they're crucial drugs, they
have serious side effects that limit their use.

Specialists are watching the capsaicin research because it promises a
one-time dose that works inside the wound, not body-wide, and wouldn't
tether patients to an IV when they're starting physical therapy.

"It's in and it's done," Viscusi explains. "You can't abuse it. You can't
misuse it."

"There's been an enormous effort to try and develop alternatives to opioids
with the same strength but not too much success," adds Dr. Clifford Woolf of
Harvard and Massachusetts General Hospital. "We think we're moving toward
it."

His team is trying a different approach: Standard lidocaine injections numb
all the surrounding tissue. Woolf and colleagues slipped lidocaine inside
just pain-sensing neurons, by opening them with a tiny dose of capsaicin.
Rats given the injections ran around normally while not noticing heat
applied to their paws, they reported in the journal Nature this month.

That's years away from trying in people, and would have to be done in a way
to avoid even a quick capsaicin burn.

In a third approach, Iadarola and NIH colleagues hope to soon test a
capsaicin cousin called resiniferatoxin in advanced cancer patients whose
pain no longer is relieved by opioids. Injections into the spinal columns of
cancer-riddled dogs did more than temporarily numb _ it severed some nerve
connections.

... Access denied --- nah, nah, nah, nah, nah

That's interesting to me because I was commenting to my PCP last week that
Bio-Freeze had helped much more with this post-surgical pain I've had than
Sore-No-More had.  That didn't make much sense to me as SNM has the same
basic active ingredients as BF, with capsaicin added (and in a different
base).  He said capsaicin can take up to a week of daily use topically to
have positive effects and that's what he always tells people who are trying
it.  I hadn't heard that angle before, I always use SNM to get me through the
really bad days and long drives and stuff like that.