Metformin extended-release usually refers to metformin extended-release tablets, which take effect about 1 hour after taking the medication and last for about 24 hours. Metformin is the first-line drug used in the treatment of type 2 diabetes mellitus, with significant glucose-lowering effects, and is recommended in combination with diet and exercise therapy. It can also be combined with medications such as sulfonylurea hypoglycemic agents or insulin. Because of its weight-lowering effect, it is especially suitable for overweight or obese patients with type 2 diabetes mellitus, and it can also be used for patients with type 1 diabetes mellitus whose blood glucose fluctuates greatly after the application of insulin. Metformin extended-release tablets usually take effect 1 hour after taking the medicine, and maintain the effect in the body for about 24 hours. The exact time is affected by diet, patient’s kidney function and other factors. Common adverse reactions to metformin include gastrointestinal reactions, skin irritation and lactic acidosis. It is contraindicated in patients with serious complications, pregnant women, lactation, alcoholism, and severe renal insufficiency. Metformin extended-release tablets should be taken under medical supervision.