What is Metformin? - Definition, Classification & Uses

Instructor: Scott Keane

Scott has a Bachelor's degree in Nursing, a Master's degree in Christian Studies, and has taught college level nursing.

Metformin is a medication used for type 2 diabetes and two other conditions that benefit from lowering blood sugars. You can learn more about this widely used antidiabetic drug in this lesson.

What Is Metformin?

Minnie just found out she has diabetes. She is upset because she believes people with diabetes cannot eat any 'white' foods. Buttery mashed potatoes with hot sausage gravy are one of Minnie's favorite indulgences. In addition, her doctor started her on a medication to help manage her type 2 diabetes. Minnie is afraid she won't be able to eat her favorite foods, and the new pill will make her gain weight.

As her nurse, you try to ease some of Minnie's fears. You first tell her that she can still have her favorite foods if she eats small amounts and takes her medication called metformin. Metformin is an anti-diabetic medication that reduces the amount of blood sugar (glucose) the liver releases and helps muscles use glucose more effectively.

How Does Metformin Work?

You begin helping Minnie understand how metformin works by telling her about type 2 diabetes. People use sugar (glucose) for energy. Glucose travels through our bodies in the blood. The pancreas makes a hormone called insulin that allows glucose to travel from the blood into the muscles and organs. If we go a long time without eating and our blood sugar drops, our livers release stored glucose to help with our energy needs.

Diabetes results when this carefully balanced system does not work well. Type 2 diabetes (non-insulin dependent) happens when we have too little insulin from our pancreas, and the insulin we have is unable to work effectively, which is called insulin resistance. This makes our blood glucose rise to harmful levels. With type 2 diabetes, our liver may release too much glucose, causing high levels of blood sugar.

You explain that metformin works in three ways to control blood sugar levels in people with type 2 diabetes. It acts on the liver to slow the release of glucose. It also helps insulin work more effectively by increasing insulin sensitivity of body tissues. Metformin also slows the absorption of glucose from the intestine.

Metformin Classification

Metformin is classified as a biguanide, a group of anti-diabetic drugs that lowers blood sugar. Biguanides originate from a lilac bush preparation that have long been used in herbal medicine. In 1957, a French doctor named one biguanide 'Glucophage,' which means 'glucose eater.' Today we know that biguanides, and thus metformin, do not eat glucose to lower blood sugar. Metformin slows the release of glucose from the liver, slows blood glucose uptake from the intestine, and increases insulin sensitivity.

Other Uses for Metformin

Minnie has heard that metformin is sometimes used to treat other conditions besides type 2 diabetes. You tell her that metformin can be effective for people with metabolic syndrome and polycystic ovary syndrome.

Metabolic syndrome is also called syndrome X or insulin resistance syndrome. People with metabolic syndrome usually have a large amount of fat around their waist and in their blood. Fat, or lipids, in blood can be stored in the walls of arteries and in the liver or muscles. Stored fat prevents insulin from allowing glucose into muscle and organ cells. It also allows the liver to release too much glucose into the blood. High blood glucose (hyperglycemia) and high blood fat (hyperlipidemia) follow.

Hyperglycemia and hyperlipidemia contribute to kidney problems, liver disease, and high blood pressure. Metformin helps people with metabolic syndrome by slowing the release of glucose from the liver and increasing the ability of muscles to uptake glucose, making them less resistant to insulin and allowing blood sugar and fat levels drop. Metformin also slows the uptake of glucose from the intestine, further lowering blood sugar.

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