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Polyneuropathy Symptoms
Symptoms improved as early as 1 week with the highest dose.
REVIEWED BY DAN ZIEGLER, MD, FRSCPE
Dan Ziegler, MD, FRCPE, from the German Diabetes Clinic, German Diabetes Center, Leibniz Institute at the Heinrich Heine University in Dusseldorf, Germany, and colleagues, conducted a multicenter, randomized, double-blind, placebo controlled trial of 181 patients with diabetes in Russia and Israel. Patients were assigned once-daily oral doses of alpha-lipoic acid 600 mg, 1,200 mg, 1,800 mg or placebo for 5 weeks after a 1-week run in period, according to a report in Diabetes Care.
The primary outcome measure in the trial was the change from baseline in the Total Symptom Score (TSS), which included stabbing pain, burning pain, paresthesia and asleep numbness of the feet. “Secondary endpoints included individual symptoms of TSS, Neuropathy Symptoms and Change score (NSC), Neuropathy Impairment Score (NIS) and patients’ global assessment of efficacy,” the researchers wrote.
Mean TSS was similar among the treatment groups at baseline, on average, and decreased by 4.9 points in the 600-mg alpha-lipoic acid group (51%), 4.5 points in the 1200-mg group (48%) and 4.7 in the 1,800-mg group (52%) compared with 2.9 points (32%) among the placebo group (P<.05 vs all placebo).
“The corresponding response rates (≥50% reduction in TSS) were 62%, 50%, 56% and 26%, respectively,” Professor Ziegler wrote. “Significant improvements favoring all three alpha-lipoic acid groups were also noted for stabbing and burning pain, the NSC score, and the patients global assessment of efficacy. The NIS was numerically reduced.”
Whether the observed favorable short-term effect of alpha-lipoic acid on nerve pain and deficits can be translated into slowing the progression of diabetic neuropathy long term is unknown, the authors wrote. “However, our finding that neuropathic deficits such as impaired sensory function were improved is encouraging, because these are major risk factors in the development of neuropathic foot ulcers.”
The authors also said that, in the absence of a dose response and because higher doses resulted in increased rates of gastrointestinal side effects, 600 mg once daily seems to be the most appropriate oral dose.
Dan Ziegler MD, FRSCPE, is from German Diabetes Clinic, German Diabetes Center, Leibniz Institute at the Heinrich Heine University in Dusseldorf, Germany. Professor Ziegler is a member of the editorial board of Diabetic Microvascular Complications Today. He may be reached at dan.ziegler@
ddz.uni-duesseldorf.de.
Ziegler D, Ametov A, Barinov A, et al. Oral treatment with alpha-lipoic acid improves symptomatic diabetic polyneuropathy. Diabetes Care. 2006;29:2365-2370.
