Case Report

Metformin-Induced Vitamin B12 Deficiency Presenting as a Peripheral Neuropathy

Chronic metformin use results in vitamin B12 deficiency in 30% of patients. Exhaustion of vitamin B12 stores usually occurs after twelve to fifteen years of absolute vitamin B12 deficiency. Metformin has been available in the United States for approximately fifteen years. Vitamin B12 deficiency, which may present without anemia and…