Sitagliptin, saxagliptin, linagliptin, alogliptin
Block DPP-4, which leads to increased activity of incretins, which inhibit glucagon release, which in turn increase insulin secretion and slow gastric emptying, ultimately decreasing blood glucose levels
Potential serious adverse events include acute pancreatitis, anaphylaxis/angioedema, SJS
Diabetes medications
CHF medications
Diabetes mellitus 
Tono-Pen use
Hypertension 
Drugs of abuse
Intravenous drug use
Metformin