A Brief Review on the Association of Prolonged Metformin Therapy and Vitamin B12 Deficiency

Abstract

Type 2 Diabetes Mellitus is a fast-growing health challenge, signaled by hyperglycemia. There are two types of diabetes mellitus, Type 1 and Type 2; both are equally life threatening condition. Type 1 diabetes is a persistent autoimmune disease as a consequence of insulin deficiency, whereas in Type 2 diabetes the body either does not produce enough insulin or develops resistance to insulin. Metformin is the exclusive pharmacologic management for Type 2 diabetes mellitus and frequently prescribed drug either single or in combination with insulin or other hypoglycemic agents. Metformin has immensely improved insulin sensitivity and defend against vascular complications. Vitamin B 12 (cobalamin) has a vital role in DNA synthesis, cellular metabolism and the deficiency will lead to megaloblastic anemia. Several studies state that metformin can cause cobalamin deficiency in doses greater than 2000 mg/ day and for a time period of more than 4 years. Hence, cobalamin and calcium supplementation will reduce the occurrence of cobalamin deficiency in patients with metformin therapy. Keywords: Type 2 diabetes mellitus, Metformin, Vitamin B 12, Vitamin B 12 deficiency, Cobalamin.