The biguanide, metformin, is considered first-line treatment for type 2 diabetes. Sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor acts through the incretin pathway and has a glucose dependent mode of action. The complementary hypoglycemic properties of these drugs make fixed dose combination treatment an attractive prospect. Evidence from recent clinical trials suggests a beneficial effect of the combination on efficacy, demonstrated by significant improvement of hemoglobin A1c (HbA1c), fasting and postprandial glucose levels. The fixed dose combination is likely to have greater patient tolerability compared with monotherapy with either agent because of low rates of hypoglycemia, weight neutrality, and lower rates of side effects. High acquisition cost and paucity of long-term safety data are, however, potential barriers to their wider use. An overview of the pharmacology and clinical outcomes from recent trials of the metformin-sitagliptin combination and how the combination could fit into the type 2 diabetes treatment algorithm is presented in this review.
Keywords: DPP-4 inhibitors; incretin-based therapies; metformin; sitagliptin; type 2 diabetes.