Aims: To evaluate the efficacy and safety of short-term oral treatment with the antioxidant thioctic acid (TA) on neuropathic symptoms and deficits in patients with Type 2 diabetes mellitus with symptomatic polyneuropathy.
Methods: Patients were randomly assigned to oral treatment with 600 mg of TA t.i.d. (n = 12) or placebo (n = 12) for 3 weeks. Neuropathic symptoms (pain, burning, paraesthesiae, and numbness) in the feet were scored at weekly intervals and summarized as a Total Symptom Score (TSS). The Hamburg Pain Adjective List (HPAL) and the Neuropathy Disability Score (NDS) were assessed at baseline and day 19.
Results: At baseline the TSS, HPAL, and NDS were not significantly different between the groups. The TSS in the foot decreased from baseline to day 19 by -3.75 +/- 1.88 points (-47%) in the TA group and by -1.94 +/- 1.50 points (-24%) in the placebo group (P= 0.021 for TA vs. placebo). The total HPAL score decreased from baseline to day 19 by -2.20 +/- 1.65 points (-60%) in the TA group and by -0.96 +/- 1.32 points (-29%) in the placebo group (P = 0.072 for TA vs. placebo). The NDS decreased by -0.27 +/- 0.47 points in the TA group, whereas it slightly increased by +0.18 +/- 0.4 points in the placebo group (P = 0.025 for TA vs. placebo). No differences between the groups were noted regarding the rates of adverse events.
Conclusions: These preliminary findings indicate that oral treatment with 600 mg of TA t.i.d. for 3 weeks may improve symptoms and deficits resulting from polyneuropathy in Type 2 diabetic patients, without causing significant adverse reactions.