LAUSR

Type 2 diabetes mellitus (T2DM) is characterized by progressive beta cell dysfunction and insulin resistance. Pharmacotherapy to treat dysregulated glucose metabolism focuses on augmenting the insulin response to hyperglycemia, improving insulin sensitivity or altering glucose disposal through the gut or urine. Dipeptidyl-peptidase-4 (DPP-4) inhibitors or ‘gliptins’ block the inactivation of glucagon-like peptide-1 (GLP-1), which stimulates glucose-dependent insulin secretion and inhibits glucagon secretion. Additionally, gastric emptying is slowed, satiety is improved, and food intake is reduced [1]. These effects are more prominent with use of GLP-1 receptor agonists. There are five DPP-4 inhibitors, including alogliptin, linagliptin, saxagliptin, and sitagliptin in the United States and Europe and vildagliptin which is only available in Europe (Table 1). This class of anti-hyperglycemic therapy is orally administered once per day with the exception of vildagliptin which is dosed twice per day. DPP-4 inhibitors can be taken without regard to food. DPP-4 inhibitors are not recommended for use as initial monotherapy for T2DM treatment [3]. They are most commonly prescribed in combination with lifestyle modification and metformin, sulfonylureas, thiazolidinediones, and/or basal insulin, but select patients intolerant to metformin have been successfully treated with DPP-4 inhibitor monotherapy. There are a number of combination products available, including gliptin–metformin and gliptin–sodium glucose transporter-2 inhibitor products. There is a paucity of direct head-to-head studies of DPP-4 inhibitors. Most comparisons are indirect. Evaluation of singular beneficial effects have been published, such as effects on cholesterol, and attributed to one particular drug within the class; however, it is reasonable to consider that these effects may be applicable across the class of medications.