Clinical Medicine Reviews in Vascular Health

Type 2 diabetes is a metabolic disease that is characterized by two important defects: insulin resistance and a defect in the integrated function of pancreatic islets. Metformin is the first-line therapy in type 2 diabetes and improves insulin resistance by reducing hepatic glucose output. Sitagliptin is the first DPP-4 (dipeptidyl-peptidase-4) inhibitor that was introduced into type 2 diabetes therapy in 2006. It raises endogenous plasma concentrations of the incretin hormone GLP-1 (glucagon-like peptide-1) and thereby restores glucose dependent insulin- and glucagon secretions of the pancreatic beta- and alpha-cells, respectively. Metformin and sitagliptin combination therapy therefore offers a beneficial and complementary addition of two agents acting on important defects in type 2 diabetes. Both agents can be given either in a free combination or as a fixed dose combination. This article reviews the published clinical studies on a metformin and sitagliptin combination therapy that improves glycaemic parameters more potently than either agent alone and is well tolerated.