Metformin (Glucophage) is the standard first line therapy for patients with type 2 diabetes mellitus. The landmark UK Prospective Diabetes Study Group demonstrated significant reduction in the risk of myocardial infarction and overall mortality in overweight patients with type 2 diabetes treated with metformin and metformin was more effective in controlling blood glucose compared with lifestyle only diet-based policy. The observed improvement of blood glucose was not associated with weight gain or hypoglycaemia in contrast to treatment with either a sulphonylurea or insulin.