Health Library

Metformin (By mouth)

Metformin Hydrochloride (met-FOR-min hye-droe-KLOR-ide)

Treats type 2 diabetes.

Brand Name(s):

DM2, Glucophage, Glucophage XR, Glumetza, Riomet

When This Medicine Should Not Be Used:

How to Use This Medicine:

Liquid, Long Acting Suspension, Tablet, Long Acting Tablet, 24 Hour Tablet

• Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
• It is best to take this medicine with food or milk.
• Swallow the extended-release tablet whole. Do not crush, break, or chew it. Tell your doctor if you have trouble swallowing the tablets whole.
• Oral liquid: Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
• Extended-release oral suspension: Use the supplied dosing cup to measure the mixed medicine. Ask your pharmacist for a dosing cup if you do not have one.
• Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
• Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Some medicines can affect how metformin works. Tell your doctor if you are using any of the following:
  • Acetazolamide, cimetidine, dichlorphenamide, dolutegravir, isoniazid, nicotinic acid, phenytoin, ranolazine, topiramate, vandetanib, zonisamide
  • Birth control pills
  • Blood pressure medicine
  • Diuretic (water pill)
  • Phenothiazine medicine
  • Steroid medicine
  • Thyroid medicine
• Do not drink alcohol while you are using this medicine.

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, heart or blood vessel disease, heart failure, blood circulation problems, anemia, metabolic acidosis, an adrenal gland or pituitary gland disorder, vitamin B12 deficiency, or had a heart attack. Tell your doctor if you drink alcohol.
• Too much of this medicine can cause a rare, but serious condition called lactic acidosis.
• Part of the extended-release tablet may pass in your stool. This is normal.
• Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine before you have surgery, an x-ray, CT scan, or other medical test.
• This medicine may cause some premenopausal women who do not have regular monthly periods to ovulate. This can increase the chance of pregnancy. If you are a woman of childbearing potential, discuss birth control options with your doctor.
• Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Confusion, fast heartbeat, increased hunger, shakiness
• Fever or chills
• Stomach pain, nausea, vomiting, muscle pain or cramping
• Trouble breathing, slow heartbeat, lightheadedness, dizziness
• Unusual tiredness or weakness

If you notice these less serious side effects, talk with your doctor:

• Diarrhea, gas
• Metallic taste in mouth

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 9/6/2024