Dipeptidyl peptidase-4 ( DPP-4) inhibitors represent a new class of oral antihyperglycemic agents to treat patients with type 2 diabetes. 1 DPP-4 inhibitors improve fasting and postprandial glycemic control without hypoglycemia or weight gain. 1 This article focuses on the physiology, clinical pharmacology, tolerability, and clinical utility of the DPP-4 inhibitor sitagliptin in the management of type 2 diabetes.