prescribe it for diabetic neuropathy, its usefulness is still
to be determined. Sold under the trademark Qutenza,
the method—approved by the FDA to treat a different
kind of nerve pain—uses a large dose of capsaicin to get
the nerves overexcited. Like a man shouting himself
hoarse, the nerves temporarily lose their “voice” and
can’t send pain signals to the brain for a while, in part
because they’ve retracted from the surface of the skin.
“It causes pain and depletes pain signaling,” says Smith.
“Afterward, you can go for months without nerves ;ring.”
The dose is applied by a doctor, who uses a painkiller so
you can’t actually feel the burn. One treatment is often
enough to achieve an effect. Smith is also using capsaicin
in experiments to measure nerve regeneration in people
undergoing gastric bypass surgery to see if weight loss
has an effect on nerve function and growth.
Virus Another unusual approach comes from Texas
Tech University Health Sciences Center researcher
Munmun Chattopadhyay, PhD. With the help of a grant
from the American Diabetes Association, she’s using
modi;ed herpes simplex viruses—the kind that give you
cold sores—to treat neuropathic pain. “If we can ;nd
a treatment at the pain phase, maybe we can delay or
prevent some of the neuropathy,” Chattopadhyay says.
Between breakouts, the herpes virus hides in nerve
cells, making it a possible delivery vehicle for pain-
dampening chemicals. Before injecting the virus into
the feet of rats with an experimental form of type 1
diabetes, Chattopadhyay modi;es the virus in two
important ways: First, she turns off the genes that cause
the virus to multiply, preventing it from causing cold
sores. Then Chattopadhyay and colleagues add genes that
instruct it to produce a chemical that blocks the nerve
from sending signals.
Chattopadhyay’s experiments are still only in rats,
though. For now, all of the methods approved for use
in humans are limited: They work in some patients but
not others, or need different dosages to take effect. It’s
important to work with your health care team to ;nd
the right combination for you. “If someone has painful
neuropathy, they have to have realistic expectations—
none of these treatments takes away pain altogether,”
says Perkins. “They tend to take the edge off so people
can get better sleep or function better.”
SEARCHING FOR A CURE
Curing neuropathy, rather than just treating its
symptoms, is even trickier. “There have been decades of
research on therapies that might heal nerves, and they’ve
mostly been failures,” says Perkins.