However, because of the postintroduction problems arising with troglitazone, an initial ALT should be done when starting any of these agents. An ALT of 2.5 times the upper limit of normal is a contraindication to starting, and 3 times the upper limit of normal is an indication for discontinuing them. Both new agents can cause weight gain, edema, and a mild anemia. They are not approved for use in Type 1 diabetes mellitus. Metformin is now approved to be used with insulin.
Metformin decreases gluconeogenesis and increases insulin sensitivity.
It has a favorable effect upon lipids. Unlike the Rezulin-like drugs, patients tend to maintain or decrease their weights with metformin. It is indicated only for Type 2 diabetes mellitus and can be used as monotherapy. It is also approved to be used with sulfonylureas, insulin, and the thiazolidinediones. It does not cause hypoglycemia.