Key takeaways
Metformin (Glumetza) and sitagliptin (Januvia) are both oral medications used to treat Type 2 diabetes. They help control blood sugar levels, but they belong to different medication classes. Metformin is a biguanide that works by lowering the amount of sugar your body makes or absorbs and improving insulin use. Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that helps your body release more insulin and reduces sugar production. Metformin is usually taken once or twice daily, while sitagliptin is typically taken once a day. Metformin is available in both short-acting and long-acting forms, and it can also be found as a liquid, whereas sitagliptin is only available in tablet form. Common side effects of metformin include diarrhea and nausea, while sitagliptin may cause a runny nose and sore throat. Metformin can lead to lactic acidosis, or acid in the blood—a serious condition, especially if you have kidney problems. Sitagliptin may cause joint pain and, rarely, pancreatitis. Both medications can be used together for better blood sugar control, combining diabetes medications can increase your risk of low blood sugar.
