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Biguanides (Metformin) for Prediabetes and Type 2 Diabetes


Table of Contents


Biguanides (Metformin) for Prediabetes and Type 2 Diabetes

Examples

Generic NameBrand Name
metforminGlucophage
long-acting metforminGlucophage XR, Glumetza, Fortamet
liquid metforminRiomet

Sometimes metformin is combined with other diabetes medicines in one pill. For example:

How It Works

Biguanides lower blood sugar by:

Metformin does not cause the pancreas to produce more insulin. It should not cause low blood sugar (hypoglycemia) or weight gain, unless it is taken in combination with medicines that do. Some people may lose weight when starting this medicine.

Why It Is Used

These medicines are used to treat insulin resistance common to people with prediabetes, type 2 diabetes, and polycystic ovarian syndrome.

How Well It Works

Type 2 diabetes is a disease that can get worse over time, so medicines may need to change.

Diabetes medicines work best for people who are being active and eating healthy foods. Studies have suggested that metformin lowers hemoglobin A1c by 1% to 2%.1

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

Call 911 or other emergency services right away if you have:

Call your doctor right away if you have:

Common side effects of this medicine include:

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

When a person begins taking metformin, the dosage usually is increased gradually to prevent side effects. You may also reduce nausea by taking the medicine with food.

Over time, blood levels of vitamin B12 can decrease in some people who take metformin. If you have been taking metformin for more than a few years, check with your doctor about getting a vitamin B12 test.

Lactic acidosis may occur in people who have kidney or liver failure, have low levels of oxygen in their blood (hypoxia), abuse alcohol, have a severe infection, or are dehydrated. It can also result if metformin is taken when a person has surgery or X-ray studies that use a dye. Be sure all your doctors know that you are taking this medicine if you need a test that involves the use of a dye or if you are having surgery. You may have to stop taking metformin temporarily.

Women who have stopped menstruating before they start taking metformin may begin menstruating again and may become pregnant.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

If you are pregnant, breast-feeding, or planning to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.

Checkups

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF) to help you understand this medication.

References

Citations

  1. Inzucchi SE, et al. (2012). Management of hyperglycemia in type 2 diabetes: A patient-centered approach. Diabetes Care, 35(6): 1364–1379.

Credits for Biguanides (Metformin) for Prediabetes and Type 2 Diabetes

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer David C.W. Lau, MD, PhD, FRCPC - Endocrinology
Last Revised July 11, 2013

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