Thioctic acid (alpha-lipoic acid) a natural co-factor in mitochondrial dehydrogenase complexes, is a significant biological antioxidant with a neuroprotective effect in experimental diabetic neuropathy. These positive effects are used with increasing frequency in the treatment of symptomatic diabetic neuropathy, in particular its painful distal symmetric form. In a 100-day ambulatory open multicentre study the authors investigated the effect of thioctic acid on symptomatic distal symmetrical diabetic neuropathy in 69 patients with NIDDM. The preparation was administered, 600 mg/day, for 10 days in an intravenous infusion and for another 90 days by the oral route. The authors evaluated subjective positive neuropathic symptoms (pain, paraesthesia, spasms) as well as objective neuropathic parame- ters (threshold of vibration perception – VPT and conduction studies of sensory and motor nerves of the lower extremities). The authors followed up the effect of treatment in particular during the parenteral and oral administration of the preparation and throughout the study. The investigation confirmed a statistically significant effect of thioctic acid in grades 1 to 3 diabetic neuropathy on the regression of subjective neuropathic manifestations. Conversely it did not confirm improvement of the vibration perception threshold nor improvement of parameters of conduction studies.

        Key words: diabetic neuropathy, thioctic acid, oxidative stress, threshold of vibration perception, conduction study