Overview of clinically approved oral antidiabetic agents for the treatment of type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is caused by insulin resistance and characterized by progressive pancreatic β-cell dysfunction. This articles reviews the application and limitations of currently approved oral drugs for the treatment of T2DM. Data were retrieved from the literature and well-recognized drug-related databases. Although lifestyle modifications and metformin are the cornerstones of the initial management of T2DM, there is an increasing array of second- and third-line pharmacological agents, including sulphonylureas, insulin, thiazolidinediones and glitazones, α-glucosidase inhibitors, glucagon-like peptide-1 agonists, dipeptidyl peptidase 4 inhibitors and the amylin receptor agonist pramlintide. Current T2DM treatment focuses on reducing blood glucose levels via different mechanisms, including nuclear hormone receptors, nucleic acid binding proteins, transcription factors, voltage-gated K(+) channels, glucosidase, G-protein-coupled receptors and non-receptor serine/threonine protein kinase. Extensive efforts are needed to address the pathogenesis of T2DM, which may facilitate the development of new therapies and the identification of new therapeutic targets to overcome the shortcomings of currently available drugs for T2DM and to achieve therapeutic goals.