Globally in diabetes Metformin no doubt is the first and the best choice in T2DM and is the most widely used drug globally. Will long term use of Metformin worsen peripheral neuropathy?

    A prospective case-control study by Wile DJ and Toth C (Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada) was conducted in patients with type 2 diabetes and concurrent symptomatic peripheral neuropathy, comparing those who had received >6 months of metformin therapy with those without metformin exposure. Comparisons were made using clinical (Toronto Clinical Scoring System and Neuropathy Impairment Score), laboratory (serum cobalamin (Cbl), fasting homocysteine (Hcy), and fasting methylmalonic acid (MMA)), and electrophysiological measures (nerve conduction studies).

    From the researchers point of view the possible reason for severe incidence of peripheral neuropathy in long-term use of metformin, as observed, is associated with malabsorption of vitamin B(12) ([Cbl]) and elevated (Hcy) and (MMA) levels, which may have deleterious effects on peripheral nerves.

    At the beginning and during metformin therapy, frequent screening for Cbl deficiency and systemic Cbl therapy should be considered to detect potential secondary causes of worsening peripheral neuropathy.