Epalrestat is a novel aldose reductase inhibitor which has been proven to have beneficial effects in diabetic neuropathy in many controlled clinical trials. It has been suggested that accumulation of sorbitol in certain cells occurring only in conditions of hyperglycemia and resulting in a hyperosmotic effect, may be involved in the pathogenesis of some diabetic complications. Epalrestat inhibits sorbitol production and prevents further complications. This agent has no influence on blood glucose concentrations.
While Diabetic neuropathy is one of the most common long-term complications in patients with diabetes mellitus, with a prevalence of 60-70% in the United States. Treatment options include antidepressants, anticonvulsants, tramadol, and capsaicin. These agents are modestly effective for symptomatic relief, but they do not affect the underlying pathology nor do they slow progression of the disease.
Now it has been confirmed in diabetic animal experiments that epalrestat improved nerve-conduction velocity, and this was accompanied by an improvement of sorbitol levels and Na+/K+- AT Pase activity in the nerve. An improvement in the morphological abnormalities of the nerves was also observed in epalrestat treated diabetics rats. Then, a placebo-controlled double-blind clinical study of epalrestat was carried out and the effectiveness of the drug against diabetic neuropathy documented.