Generic Metformin

Common use

Metformin is used for controlling high blood sugar in people with type 2 diabetes in adults and children. Controlling high blood sugar helps prevent kidney damage, blindness, nerve problems, loss of limbs, and sexual function problems. Proper control of diabetes may also lessen your risk of a heart attack or stroke. Metformin treats by increasing the sensitivity of liver, muscle, fat, and other tissues to the uptake and effects of insulin and by helping to restore your body's proper response to the insulin you naturally produce. These actions lower the level of sugar in the blood. It may be used alone or in combination with other diabetic medications. Metformin has been found to be especially useful in delaying problems associated with diabetes for overweight people with diabetes.



Dosage and direction

The recommended adult dose of Metformin ranges from 500 mg 3 or 4 times a day to 850 mg 2 or 3 times a day. The maximum daily dose should not exceed 2,550 mg daily. You should take it with food with a full glass of water once daily with the evening meal whenever possible to reduce the risk of nausea and vomiting. Swallow this medication whole. Do not crush, chew, or break the tablets. Doing so can destroy the long action of the drug and may increase side effects. To be sure that the medication is working well, monitor your blood glucose on a regular basis as directed by your doctor or diabetes educator. For pediatric patients 10-16 years of age, the starting dose is 500 mg twice a day. The dose can be increased by 500 mg weekly up to a maximum dose of 2000 mg. The dosage is based on your medical condition and response to therapy. Follow your doctor's directions carefully. Use this medication regularly in order to get the most benefit from it. Remember to use it at the same time each day. It may take up to 2 weeks before the full benefit of this drug takes effect.



Precautions

Tell your doctor if you have liver or heart disease even in a history. You should not use this medication if you are allergic to Metformin, or if you are in a state of diabetic ketoacidosis (call your doctor for treatment with insulin). Avoid drinking alcohol that lowers blood sugar and may increase your risk of lactic acidosis while taking Metformin.



Contraindications

Metformin is contraindicated in patients with renal disease or renal dysfunction, known hypersensitivity to metformin, acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma. Diabetic ketoacidosis should be treated with insulin. People who is experiencing or recovering from severe infections, trauma, or surgery, is pregnant, is suffering severe dehydration, is undergoing radiologic studies involving use of iodinated contrast materials, drinks large amounts of alcohol in the short term or on a regular basis, has diseases associated with lack of oxygen to the tissues such as cardio-respiratory insufficiency, has reduced kidney function, has severe liver disease, has type 1 diabetes (they should always be using insulin), has very poor blood glucose control (they should not take this medication as the only anti-diabetic agent) shoul not use Metformin.



Possible side effects

The most common side effects with metformin are nausea, vomiting, gas, bloating, diarrhea and loss of appetite. These side effects are related to the dose of the medication and may decrease if the dose is reduced. A serious but rare side effect of metformin is lactic acidosis. The symptoms of lactic acidosis are weakness, trouble breathing, abnormal heartbeats, unusual muscle pain, stomach discomfort, light-headedness and feeling cold. Patients at risk for lactic acidosis include those with reduced function of the kidneys or liver, congestive heart failure, severe acute illnesses, and dehydration.



Drug interactions

Tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use. Combination of Cimetidine (Tagamet) and Metformin may increase the frequency of side effects.



Missed dose

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.



Overdose

Get emergency medical help if you have any of these symptoms of lactic acidosis: weakness, increasing sleepiness, slow heart rate, cold feeling, muscle pain, shortness of breath, stomach pain, feeling light-headed, and fainting.



Storage

Metformin should be stored at room temperature between 20-25°C (68-77°F).



Disclaimer

We provide only general information about medications which does not cover all directions, possible drug integrations, or precautions. Information at the site cannot be used for self-treatment and self-diagnosis. Any specific instructions for a particular patient should be agreed with your health care adviser or doctor in charge of the case. We disclaim reliability of this information and mistakes it could contain. We are not responsible for any direct, indirect, special or other indirect damage as a result of any use of the information on this site and also for consequences of self-treatment.

Clinical Verification

Last Clinically Updated: August 15, 2026

Written By

Dr. Elena Vance, PharmD

Clinical Specialist in Neuropharmacology

Fact Checked By

Marcus Thorne, MS

Biomedical Data & FDA Label Verification

Medically Reviewed By

Dr. Arthur Campbell, MD

Board-Certified Psychiatrist (ABPN)