Biguanides

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Brand Name (Generic Name)

Glucophage (metformin)

Fortamet (metformin hydrochloride)
extended release

Riomet (metformin HCl oral solution)
liquid metformin

Biguanides are another type of diabetes medicine. Metformin (met-FOR-min) is a biguanide that helps lower blood glucose by making sure your liver does not make too much glucose. Metformin also lowers the amount of insulin in your body. The August 2006 guidelines from the ADA and the European Association for the Study of Diabetes recommends the inclusion of metformin (along with diet and excercise) in initial diabetes treatment.

You may lose a few pounds when you start to take metformin. This weight loss can help you control your blood glucose. Metformin can also improve blood fat and cholesterol levels, which are often not normal if you have type 2 diabetes.

A good thing about metformin is that it does not cause blood glucose to get too low (hypoglycemia) when it is the only diabetes medicine you take.

How often should I take metformin?

Two or three times a day.

When should I take metformin?

With a meal. Your doctor should tell you which meals to take it with.

What are possible side effects?

• Metformin can make you sick if you drink more than about 2 to 4 alcoholic drinks a week. If you drink more than that, tell your doctor. You should probably not take metformin.
• If you already have a kidney problem, taking metformin may make it worse. Make sure that, before you start taking metformin, your doctor knows your kidneys work well.
• If you are vomiting, have diarrhea, and can't drink enough fluids, you may need to stop taking metformin for a few days.
• Once in a while people on metformin can become weak, tired, or dizzy and have trouble breathing. If you ever have these problems, call your doctor or get medical help right away.
• You may have nausea, diarrhea, and other stomach symptoms when you first start taking metformin. These usually go away.
• You may notice a metallic taste in your mouth.

How often should I take metformin extended release?

Once a day.

When should I take metformin extended release?

With the evening meal.

What are possible side effects?

The side effects of this medicine are the same as for metformin.

Are other diabetes medicines used with metformin extended release?

Yes, it can be used with sulfonylureas or insulin.

When should I take liquid metformin?

Dosage should be prescribed by your doctor. It must be individualized on the basis of effectiveness and tolerance, while not exceeding the maximum recommended daily dose.

What are the possible side effects?

Possible side effects include diarrhea, nausea/vomiting, flatulence, asthenia, indigestion, abdominal discomfort, and headache.

What to know about having surgery or medical tests with dye?

If you are having a medical test with dye, tell the doctor you take metformin. You may be told to stop taking metformin the day of the test and not take metformin again for 48 hours.

If you are having surgery, tell the doctor you take metformin. You should be told to stop taking metformin the day of the surgery. Then you should not take metformin again until you are eating and your kidneys are working normally.

SOURCE:

National Diabetes Information Clearinghouse. What I Need to Know About Diabetes Medicines. (Accessed 8/8/11.)

Reviewed by Francine Kaufman, MD.