All About Metformin-An Old But Effective Diabetes Medicine

What it Does, How to Take it, and How to Prevent Side Effects

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According to the American Diabetes Association Standards of Care, Metformin, if tolerated, is the preferred initial oral diabetes medication for Type 2 diabetes because it is the most effective. Unlike people with Type 1 diabetes, people with Type 2 diabetes make insulin. The problem is that they are either not making enough insulin or the insulin they do make isn't being used efficiently. Metformin is a weight neutral medication that helps the body use insulin.

Like all medicines, however, Metformin can produce some side effects. The biggest complaint people have about Metformin is that it causes gas and diarrhea. Other side effects that are less common include lactic acidosis, shortness of breath and swelling. Long term use of Metformin may result in B12 deficiency.

If you are someone with Type 2 diabetes, taking Metformin and experiencing less severe sides effects such as diarrhea and gas, you should contact your health care provider to make sure you are taking it correctly. If, on the other hand, you are experiencing severe side effects such as shortness of breath, contact your health care provider immediately.

How Does Metformin Work?

Metformin belongs to a class of drugs called biguanides. Metformin helps to lower blood sugars by utilizing insulin and reducing insulin resistance by making your body more sensitive to insulin. Generally speaking, people with Type 2 diabetes carry excess weight — fat cells prevent insulin from doing its job, ultimately causing the cells to become resistant to insulin.

When cells become resistant to insulin, insulin is unable to take sugar from the blood stream to the cells to use for energy, and instead the sugar remains in the blood. As a result, the liver responds by making more sugar because it thinks the body needs it for fuel and the pancreas responds by making more insulin.

You wind up with chaos - high blood sugars and high insulin levels. Metformin helps to restore normalcy by increasing insulin sensitivity and reducing the production of sugar made by the liver. 

When Should You Take Metformin?

It is recommended to take Metformin with meals because food increases its absorption in the stomach and reduces side effects - stomach cramps, diarrhea, and nausea. Typically, most people new to Metformin will take it with the largest meal. To remember to take Metformin, you should try to take it around the same time(s) every day.

Increase Your Dose Gradually

Metformin is a medicine that should be increased or titrated gradually to ease any stomach discomfort. How long this takes will depend on what your health care provider prescribes and how you respond to the medication (the medication has several doses). For example, a person who is new to Metformin and has been prescribed 2000mg twice a day, may start by taking 500mg once daily with dinner for one week. At week two, the patient will take 500mg with breakfast and 500mg with dinner. At week three, the patient will take 1000mg with dinner and 500mg with breakfast. And at week four, the patient will be at therapeutic goal - taking 1000mg with breakfast and 1000mg with dinner.

Throughout the duration of titration, the patient should monitor his blood sugars. If the person experiences low blood sugars or any other side effects, he should contact his health care provider so that the medication could be adjusted accordingly. When in doubt - always ask.

Ask About The Extended Release Version

If you are experiencing persistent side effects such as gas or diarrhea, ask your health care provider about the extended release version of this medicine - it is a time released version of the medicine which may help to prevent the gastrointestinal side effects. The extended release version is usually taken once per day with the evening meal.

Other Common Names:

If you are experiencing gas, diarrhea and stomach upset, but are not sure if you are taking Metformin look at your prescription label. Other common names for Metformin include:

  • Fortamet®
  • Glucophage®
  • Glucophage XR®
  • Glumetza®
  • Riomet®

Metformin can also be combined with other diabetes medicines. If you are unsure what you are taking or how your medicines work you should ask your health care provider. 

  • Actoplus Met® (containing Metformin, Pioglitazone)
  • Avandamet® (containing Metformin, Rosiglitazone)
  • Glucovance®  (containing Metformin, Glyburide)
  • Invokamet™ (containing Metformin HCl/Canagliflozin)
  • Janumet® (containing Metformin, Sitagliptin)
  • Janumet® XR (containing Metformin, Sitagliptin)
  • Jentadueto® (containing Metformin, Linagliptin)
  • Kazano® (containing Metformin/Algoliptin)
  • Kombiglyze® XR (containing Metformin, Saxagliptin)
  • Metaglip® (containing  Metformin, Glipizide)
  • Prandimet® (containing Metformin, Repaglinide)
  • Synjardi® (containing Metformin, Jardiance)
  • Xigudo® XR (containing Metformin HCl, Dapagliflozin)


Austin, Roger. Should I Take Metformin with Food. Diabetes Forecast. 

American Diabetes Association. Standards of Medical Care in Diabetes – 2014. Diabetes Care. 2014 Jan; 37 Suppl 1: S14-80.

US National Library of Medication. National Institute of Health. Metformin.

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