People with diabetes often suffer from chronic foot pain because of nerve damage, but relief may be at hand.

Taiwanese doctors have shown that the pain can be reduced significantly by injections of botulinum toxin type A — better known as Botox — into the skin on top of the foot.

Dr. Chaur-Jong Hu and his associates at Taipei Medical University tested the treatment in 18 patients with Type 2 diabetes who had nerve-related pain in both feet.

The participants were assigned randomly to get injections of Botox or saline, then 12 crossed over to receive the opposite treatment a few weeks later.

A local anesthetic gel was applied to the injection sites first, and then the injections were administered into the skin (rather than into muscles) at 12 sites across the top of the foot, the team explained in the medical journal Neurology.

At the start of the study, the average pain score on a scale of 0-10 points was 6.36. There were significant differences in the decrease in pain scores between the Botox and saline injections during each 12-week period.

Specifically, at 12 weeks, the score was reduced by 2.53 points with Botox injections compared with 0.53 points with the saline injections.

Moreover, 44 percent of the subjects had a reduction of at least 3 points in their pain score within 12 weeks of recieving the Botox injections.

Another added and unexpected benefit discovered in the study was that patients are able to sleep much better after the treatments.

Hu’s team concluded that intradermal Botox injections “are an effective and safe method of relieving diabetic neuropathic pain in the feet.” However, “the detailed underlying mechanisms, optimal dosage, and precise course of therapy require further evaluation.”

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When it was first discovered a year ago about surprising new evidence that Botox and other drugs containing the neurotoxin botulinum could travel from the site of injection to the brain, it wasn’t clear whether this posed a threat to patients (the study cited described was done on lab animals).

Earlier this week however, the Food and Drug Administration announced that the risk was all too real: effective immediately, the FDA will now require Botox, Myobloc and all other botulinum treatments to carry what is known as a “black box warning” — the strongest FDA warning of record — alerting doctors and patients alike that the toxin can spread to distant parts of the body, well enough away from the injection site(s), posing serious risks such as trouble breathing and swallowing.

The FDA is also requiring manufacturers to send doctors and all other licensed practitioners a letter warning of the risk.

The action comes in response to a petition from Public Citizen, which in 2008 asked FDA to require both a black box and the warning letters. Initially, it was expected that FDA would have limited the warnings to non-cosmetic uses of the drugs, since that’s where most of the problems with adverse side effects had occurred (Editors note: botulinum is used to treat cervical dystonia, eyelid spasms and a few other medical conditions in addition to cosmetic applications such as treating frown lines), especially in unapproved uses such a limb spasticity in children with cerebral palsy.

But the administration said it found 225 cases in which the drug had migrated beyond the injection site, sometimes as far as to deep internal tissue. That was alarming enough to justify the black-box decision, even on cosmetic Botox.

According to the FDA, “there is insufficient information to fully characterize the safety profile and potential risk factors for spread of botulinum toxin at this time, given that the mechanism by which spread may occur has not been confirmed…Based on available information, it is not possible to precisely predict the role of injection site, injection technique, or dose in the spread of toxin or severity of the event. Therefore, we are seeking safety labeling changes for the both the dermatologic and neurologic indications.”

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