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Insert E: Glucophage, Glucophage XR, and Riomet (Biguanides)

Biguanide (by-GWAH-nyd)​​

Brand Name​ Generic Name​
 __ Glucophage (GLOO-coh-fahj)​ ​ __ metformin (met-FOR-min)
 __ Glucophage XR​  __ metformin-long-acting​
​ __ Riomet (RY-oh-met) ​ __ metformin-liquid

The American Diabetes Association recommends metformin (Glucophage, Glucophage XR, Riomet) as the first choice of diabetes medicine for most people with type 2 diabetes. Metformin can be taken alone or with other diabetes medicines. See Insert K for information about combination pills that contain both metformin and another diabetes medicine.

What does this ​type of medicine do?

This type of medicine, which comes in pill or liquid form, lowers the amount of glucose made by your liver. Then your blood glucose levels don’t go too high. This type of medicine also helps treat insulin resistance. With insulin resistance, your body doesn’t use insulin the way it should. When your insulin works properly, your blood glucose levels stay on target and your cells get the energy they need. This type of medicine improves your cholesterol levels. It also may help you lose weight.

Who should not tak​e Glucophage, Glucophage XR, or Riomet?

Talk with your doctor about whether to take this type of medicine if

  • you have advanced kidney or liver disease
  • you drink excessive amounts of alcoholic beverages
  • you are pregnant, planning to get pregnant, or breastfeeding

What are the possible s​ide effects?

This type of pill doesn't cause low blood glucose by itself. But your risk of having low blood glucose goes up if you also take

  • diabetes pills that cause low blood glucose
  • insulin

Your doctor may ask you to take a lower dose of your other diabetes medicines while you take this type of pill.

You may have nausea, diarrhea, or an upset stomach when you first start taking this type of medicine. These side effects are likely to go away after a while.

Rarely, a serious condition called lactic acidosis occurs as a side effect of taking this medicine. Call your doctor right away if you

  • become weak and tired
  • become dizzy
  • feel very cold
  • have trouble breathing
  • have unusual muscle pain and stomach problems
  • have a sudden change in the speed or steadiness of your heartbeat

Sometimes you'll need to stop taking this type of medicine for a short time so you can avoid developing lactic acidosis. If you have severe vomiting, diarrhea, or a fever, or if you can't keep fluids down, call your doctor right away. You should also talk with your doctor well ahead of time about stopping this type of medicine if

  • you'll be having special x rays that require an injection of dye
  • you'll be having surgery

Your doctor will tell you when it's safe to start taking your medicine again.

Return to What I need to know about Diabetes Medicines

Go to Insert F: Starlix (D-Phenylalanine Derivative)


This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings through its clearinghouses and education programs to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.

This information is not copyrighted. The NIDDK encourages people to share this content freely.


December 2013