How Much Do You Know About Metformin...from daibetes Self-Management

By imsuzie2 Latest Reply 2011-04-13 22:23:27 -0500
Started 2011-04-01 05:09:12 -0500

How Much Do You Know About Metformin?

Metformin is a drug commonly used in the treatment of Type 2 diabetes. It is sold as a generic and under several brand names, including Glucophage, Glumetza, Riomet, and Fortamet. Both the American Diabetes Association (ADA) and the American Association of Clinical Endocrinologists (AACE) recommend metformin as a cornerstone of therapy for Type 2 diabetes when exercise and dietary changes aren’t enough to keep blood glucose levels in target range. The low cost of the generic forms along with a long history of use make it a good choice for many individuals with Type 2 diabetes.

Although metformin has helped many people lower their blood glucose levels, it does have some potential side effects that are worth knowing about. Understanding the risks and benefits of metformin is key to using it successfully. Take this quiz to test your knowledge of this popular diabetes medicine. (You can find the answers later in the article.)


1. How does metformin work to lower blood glucose levels?
A. It stimulates the pancreas to make more insulin.
B. It decreases the amount of glucose produced by the liver and makes it easier for cells to accept glucose from the bloodstream.
C. It slows the digestive system’s breakdown of carbohydrates into glucose, allowing more time for insulin to work.
D. It suppresses appetite, slows stomach emptying, and inhibits the release of glucagon (a hormone that raises blood glucose levels).

2. In addition to lowering blood glucose, metformin sometimes causes moderate weight loss.

3. In research studies, metformin use was associated with which of the following benefits in people with Type 2 diabetes?
A. Reduced risk of morning high blood glucose.
B. Reduced neuropathy (nerve damage).
C. Reduced retinopathy (damage to the retina, a membrane in the eye).
D. Reduced nephropathy (kidney disease).

4. Which of the following are potential side effects of metformin?
A. Insomnia.
B. Gastrointestinal upset.
C. Vitamin B12 deficiency.
D. Heart attack.

5. Metformin should be used with caution by people with nephropathy (kidney disease), severe liver disease, or decreased kidney function.

6. Under which of the following circumstances should you remind your doctor that you are taking metformin?
A. Before an x-ray test that uses an injected dye.
B. Before surgery.
C. Before starting any new drugs, for your diabetes or for any other condition.
D. Before beginning an exercise regimen.


1. B and C. Metformin works by activating an enzyme called AMP-activated protein kinase (AMPK), that in turn signals the liver to produce less glucose and encourages cells to store glucose from the bloodstream (thus lowering blood glucose levels). AMPK also affects the body’s metabolism by inhibiting the production of cholesterol and fatty acids and lowering insulin resistance. Additionally, metformin may decrease the absorption of glucose by the gastrointestinal tract, allowing more time for insulin to work and reducing postmeal spikes in blood glucose level.

2. TRUE. The change may not be dramatic, but generally, people who take metformin lose some weight within a few months of starting treatment. Metformin is different in this regard from other diabetes medicines, such as sulfonylureas (glimepiride, glyburide, glipizide), thiazolidinediones (Actos and Avandia), or insulin, which often lead to weight gain. In all of these cases, however, careful attention to food choices and portion sizes and getting regular physical activity can minimize or prevent weight gain. In the case of insulin, tailoring dose sizes to the body’s needs will also prevent weight gain as a drug side effect.

3. A, B, C, and D. Metformin reduces the overproduction of glucose by the liver, which is what frequently causes high morning blood glucose. In fact, metformin is often first prescribed because of high morning blood glucose, and research bears out its effectiveness at alleviating this common problem. Long-term research studies (those lasting five years or longer) have also shown metformin to reduce damage to the small blood vessels, a common consequence of chronic high blood glucose. Conditions that can result from this damage include neuropathy, retinopathy, and nephropathy.

4. B and C. The most common side effects of metformin are related to the intestines. Diarrhea is the most common, but some people report problems with the upper digestive tract, such as nausea or heartburn. Metformin is usually started at a low dose to reduce these side effects, then gradually increased as the body adjusts to the drug. Gastrointestinal side effects can also be reduced by taking metformin with a meal. Full benefits of metformin (including lower blood glucose) are often not seen until the dose is adjusted upward. This usually takes a couple of weeks.

Reduced vitamin B12 absorption is another possible side effect of metformin, leading to a deficiency in 10% to 30% of the people who take it. Vitamin B12 deficiency can cause anemia and nerve damage. If you take metformin, ask your doctor about having your B12 level measured and about whether you should take B12 supplements.

Use of metformin is not associated with insomnia. In addition, a long-term study of people with Type 2 diabetes treated soon after diagnosis with metformin showed a lowered risk of death, heart attack, and vascular problems; whether these benefits extend to everyone who takes it is not known.

5. TRUE. The kidneys are responsible for removing metformin from the body. In people with kidney damage, metformin can build up in the blood, leading to a rare but serious condition called lactic acidosis. However, research has shown metformin to have a protective effect on the kidneys if started before damage has been done; it does not cause kidney damage in healthy kidneys. Severe liver disease also increases a person’s risk of developing lactic acidosis. Some doctors prescribe metformin for people with mild nonalcoholic fatty liver disease. Your doctor will closely monitor your liver with blood tests if you are taking metformin and have a history of liver disease.

6. A, B, and C. Dyes that are used in some x-ray tests can, in rare instances, cause temporary kidney shutdown, possibly leading to lactic acidosis. Your doctor may advise you to stop taking metformin for two days before and two days after such an x-ray to avoid problems. Major surgery can lead to reduced fluids in the blood and sometimes reduced kidney function, raising the risk of lactic acidosis. Metformin may need to be stopped before surgery.

Like any drug, metformin can interact with certain other drugs. Before you start any new drugs, therefore, ask your doctor about potential interactions and what the symptoms of such interactions might be. Your pharmacist is another good source of information on drug interactions and side effects.

It’s always a good idea to check in with your doctor before starting an exercise program or intensifying your workouts. But taking metformin should not hinder or interfere with your ability to exercise.

22 replies

donna62M 2011-04-03 08:31:38 -0500 Report

I was on Metformin To start with…but I had a reaction to it after taking it for5 years…The Metformin put mein Lactic Acidosis…One of the scarriest time with my diabetes so far…That was the main reason I was put on insulin.

birch21 2011-04-13 19:54:29 -0500 Report

I started out on metformin when I was diagnoised and until about yr ago now I found out that I was anemic and my doctor has now put me on Janumet and also Januvia. I hope everyone out there will keep a check on their blood levels and not become anemic. Anemia is no fun at all and I am still taking iron. Don't know how long I will be on it but I will take it for as long as I have to. I had some surgery on March 1 and was told that I am still anemic so I am hoping that the iron is helping. Take care everyone and thanks for all the wonderful advice each of you give.

birch21 2011-04-13 22:23:27 -0500 Report

Thanks for the good luck wishes. No I'm not on Vitamin C but most likely should be. Thanks for the heads up on the vitamin c. I will look into that. Hope you are continuing to feel better. Thanks again.

donna62M 2011-04-13 20:21:45 -0500 Report

was anemic after having my second child…was on thoes tabs for four years…are you taking vitamin c with your iron…that helps it absorb better…good luck hope you get better soon.

echowit 2011-04-02 20:21:43 -0500 Report

It's good to know these things. Maybe I'm now 1 step closer to figuring out my constant, irritating, little "burp syndrome". (No other side effects, thank goodness)
I had some vague ideas along these lines from my initial "diabetes education" but I was so new and so scared at the time that most of was I heard didn't really sink in. This was a great refresher course. I'm bookmarking this one.

imsuzie2 2011-04-04 06:23:33 -0500 Report

You are welcome, Larry. As the Vets around here say, we are a community of friends, looking out for eachother. Everything one of us posts will help someone else. We have to take of each other!

Get a list of your questions written up for your next appointment, or, call the diabetes educator and ask them now!


Blessed617 2011-04-02 14:08:18 -0500 Report

This is very helpful information and I am going to pass it along. I notice that my question is not answered here. Can prolonged use of metformin cause an increase in the way neuropathy hits the body?

imsuzie2 2011-04-04 06:25:55 -0500 Report

I don't know. Maybe someone here has an answer…the ADA on their site, your doc or pharmacist might know. Good luck with your search. Have you tried to search neuropathy on the web, webMD, etc?


jayabee52 2011-04-02 14:12:54 -0500 Report

I don't know for sure, but I suspect that since diabetes is an individualized condition, that it also happens differently with different persons with diabetes.

I would have no Idea on even how to try to research that question.

Hopieland 2011-04-02 12:39:10 -0500 Report

I love this. I've been on Metformin for years but never really thot about the side effects or when or when not to take it. You noted some web sites where U gt info… could you share them with us? I was just wondering where I might find USEFUL info online the other day. Too many to choose from! Finding info that doesn't just scare us isn't easy, either, especially for newly Dx'd. This is so encouraging.

June Tademy
June Tademy 2011-04-01 16:28:37 -0500 Report

Metformin is the drug of choice for doctors for one it keeps you from gaining weight thereby controlling you BS. I had terrible reactions from this drug and was taken off, it did not suit my body, stomach pain,vomiting always sick, it also damaged my kidneys. One doctor kept it on me no matter what but I changed to and Endrocronologist and he gave me time released metformin, worked for awhile then stomach pain again, took me off because the damage it caused my kidneys again. So be careful and always always tell your doctor every little reaction so they can help you.

Graylin Bee
Graylin Bee 2011-04-01 12:40:31 -0500 Report

Thanks or the info. It helped me remember that while Metformin might take several weeks to kick your liver into gear, it only takes a few days to lower to a safe level to prevent major complications with some CT dyes. My Dr puzzled me this week when he suggested taking an extra dose if I had an extra carby meal. At the hospital they didn't give me metformin for the three days I ws on n ll liquid diet. They exlplined there wsn't enough crbs going in for the body to need the boost. The same was true for all the liquid diet days before other surgeries. I had the info in seperate boxes in my brain. Thanks for helping but the pieces into one place for me.

imsuzie2 2011-04-01 08:09:44 -0500 Report

I thought so too, since I did not answer all of the questions right, and I had a refresher education class last summer! There are lots of good emails I get from dLife, Diabetes Self-Management and diaTribe, and should do a better job of sharing. Did also post 1 or 2 recipes…now, if I would only cook them!!! Hugs

GabbyPA 2011-04-01 06:21:02 -0500 Report

This is great to read. Metformin is prescribed to so many first off and knowing these little tidbits can help us understand what our bodies are doing. Mine doesn't like Metformin in the start, but it calms down later. Great Q & A