Mayo clinic study finds
alpha lipoic acid decreases burning pain and numbness of neuropathy
A collaborative study between Mayo Clinic and a
medical center in Russia found that alpha lipoic acid (ALA) significantly and
rapidly reduces the frequency and severity of symptoms of the most common kind
of diabetic neuropathy. Symptoms decreased include burning and sharply cutting
pain, prickling sensations and numbness.
"There appears to be a rather large effect on the pain of diabetic neuropathy with ALA," says Peter Dyck, M.D., Mayo Clinic neurologist and peripheral nerve specialist. "The magnitude of the change is considerable. We also found some improvement in neurologic signs and nerve conduction. We were surprised by the magnitude and the rapidity of the response."
When patients were given ALA, also known as thioctic acid, the researchers found statistically significant improvement in the symptoms of diabetic sensorimotor polyneuropathy (DSPN) damage to multiple nerves caused by diabetes. The researchers measured improvement by a total symptom score, a summation of the presence, severity and duration of burning and sharply cutting pain, prickling sensations and numbness. The patients who took ALA saw a 5.7-point total symptom score improvement from the start of the trial, while those who took placebo, an inactive substance, only improved 1.8 points. ALA produced no unfavorable side effects in the patients taking this substance.
"It's very safe," says Dr. Dyck. "There have been no known complications."
The alternatives for managing the symptoms of DSPN -- narcotics, analgesics or antiepileptic drugs -- are less than ideal, according to Dr. Dyck.
Dr. Dyck says that the intravenous ALA preparation at the dosage he studied is not available to U.S. physicians. It is available in oral form and in smaller doses in drug stores.
"I think it's a promising lead for the future, in that antioxidants may be implicated in the cause of diabetic neuropathy, and ALA might conceivably be a preventative or interventative," says Dr. Dyck. "It may well be worthwhile for treatment, but I'd rather patients with diabetic neuropathy not go out swallowing large amounts of this drug yet. It isn't Food and Drug Administration-approved for this purpose."
Dr. Dyck adds that a large, multi-center trial of oral ALA is under way. "We should see what the further data show before we give this widely to patients with diabetic neuropathy," says Dr. Dyck.
The phase 3 study, which included 120 type 1 or 2 diabetic patients, ages 18-74, with DSPN. They found that ALA improves the nerve function damaged by chronic hyperglycemia, or the condition when patients' blood sugars consistently are not under proper control.
Although regulating patients' blood-sugar levels is the ideal way to prevent diabetic neuropathy, physicians have recognized that not all patients can or will control their blood sugars to the needed degree, according to Dr. Dyck. Some patients do not monitor their glucose levels or use their insulin injections or pumps often enough. For other patients, such as type 1 diabetics, blood sugars may fluctuate wildly and prove difficult to control tightly.
Source: Diabetes In Control Dot Com: Diabetes Care March 2003.
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