Metformin is a medication used in the treatment of patients with Type 2 Diabetes. Some of the brand names are Glucophage, Glumetza, and Riomet. Another common indication is in the treatment of Gestational Diabetes Mellitus. 

This drug works by decreasing glucose production, decreasing interstitial glucose absorption, and by increasing peripheral glucose uptake and insulin sensitivity.

Metformin is commonly dosed using either immediate release or extended release tablets. Initial dosing begins with 500 mg 1-2 times daily or with 850 mg once daily then titrated to a goal of 850-1000 mg twice daily.

This drug is not metabolized hepatically with around 90% being excreted in the urine. Side effects include diarrhea, flatulence, and infection. There is a black box warning for lactic acidosis.