Biguanides is a class of prescription medication used for the treatment of type 2 diabetes.

The pancreas produces insulin, a hormone, that transfers glucose (sugar) found in the bloodstream into cells in order to provide fuel. Glucose in the bloodstream comes from the food and drinks you consume. In people with type 2 diabetes, the body either does not produce sufficient quantity of insulin, or the insulin that is produced does not work as it should to transport glucose from the bloodstream to the cells.

The only biguanide to treat type 2 diabetes is metformin which is sold under several brand names, namely: Glucophage, Glucophage XR, Fortamet, Glumetza and Riomet.

What is Metformin?

Metformin, a type of biguanide, is an oral medication that is available in the form of an immediate release tablet, an extended release tablet and a solution. Metformin lowers blood glucose levels mainly by decreasing the amount of glucose produced by the liver. In addition, it increases the quantity of glucose absorbed by muscle cells and in doing so, decreases insulin resistance. 

According to the AACE guidelines, metformin is usually the first line therapy prescribed for people with type 2 diabetes, along with diet and exercise, to obtain blood glucose control. It is also used in combination therapy with other oral antidiabetic agents or insulin in those patients that need additional treatment to achieve blood glucose control.

Metformin should be taken exactly as prescribed by your doctor. It should not be taken by patients whose kidneys don’t work properly since it’s usage can increase the risk of developing a potentially deadly condition called lactic acidosis, where excessive lactic acid builds up in the bloodstream. Patients should get kidney function tests before starting metformin. Do not take metformin if you are allergic to it or any of the ingredients in the medication. Also, check with your healthcare provider about any potential drug interactions.

Some of the most common side effects reported by people taking metformin are:

  • diarrhea
  • constipation
  • nausea
  • stomach pain
  • gas

It’s very rare, but some people might experience serious side effects from taking metformin. These are:

These are not all the possible side effects of Metformin. Patients should talk to their doctor about what to expect with treatment with Metformin. Let your healthcare provider know if you experience side effects after taking metformin or any other medication for type 2 diabetes.

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Written by: Amna Rizvi | Last reviewed: May 2021