The discovery of the enteric hormone glucagon-like peptide 1 (GLP-1), and subsequent demonstration that its physiologic actions to lower blood glucose levels can be extended to the treatment of type 2 diabetes, have been important therapeutic advances.1,2 The approval of exenatide for clinical use in the United States and Europe in 2005 was the first of several GLP-1 receptor agonists (GLP-1RAs) to advance the clinical use of the dual effects of these drugs to lower glycated hemoglobin (HbA1c) and reduce body weight. This introduced a new and needed option to treat patients with diabetes. The actions of the currently available GLP-1RAs are specific for the endogenous GLP-1 receptor signaling system and thus share many pharmacodynamic characteristics. However, these agents differ in properties that alter pharmacokinetics, with dosing schedules that vary from daily to weekly injections among the various agents.
