Metformin is used as a first line treatment of type 2 diabetes. Metformin belongs to the class of drugs known as biguanides. Glucophage does not increase the body's production of insulin. Metformin is used as a first line treatment of type 2 diabetes. If the patient is taking Glucophage tablets, the starting dose is 500 mg daily with the evening meal or as directed by your doctor. Drink plenty of fluids while taking this medication unless otherwise directed by your doctor.