Treatment of diabetic neuropathy and neuropathic pain: how far have we come?

At least one of four diabetic patients is affected by distal symmetric polyneuropathy, which represents a major health problem, since it may present with partly excruciating neuropathic pain and is responsible for substantial morbidity, increased mortality, and impaired quality of life. Treatment is based on four cornerstones: 1) causal treatment aimed at (near)-normoglycemia, 2) treatment based on pathogenetic mechanisms, 3) symptomatic treatment, and 4) avoidance of risk factors and complications. Recent experimental studies suggest a multifactorial pathogenesis of diabetic neuropathy. From the clinical point of view, it is important to note that, based on these pathogenetic mechanisms, therapeutic approaches could be derived, some of which are currently being evaluated in clinical trials. Among these agents, only alpha-lipoic acid is available for treatment in several countries and epalrestat in Japan. Although several novel analgesic drugs such as duloxetine and pregabalin have recently been introduced into clinical practice, the pharmacologic treatment of chronic painful diabetic neuropathy remains a challenge for the physician. Individual tolerability remains a major aspect in any treatment decision. Epidemiological data indicate that not only increased alcohol consumption but also the traditional cardiovascular risk factors such as hypertension, smoking, and cholesterol play a role in development and progression of diabetic neuropathy and hence need to be prevented or treated.