Mechanism of Action: Glimepiride is a sulfonylurea which works by increasing the amount of insulin released by the pancreas in order to lower the blood glucose. Metformin is a biguanide which works by lowering glucose production in the liver, delaying glucose absorption from intestines and increasing the body's sensitivity to insulin. Glimepiride, Metformin and Pioglitazone. They work by different mechanisms to provide better control of blood sugar when single or dual therapy is not effective