Taking Metformin (Glucophage) for Type 2 Diabetes

If you have Type 2 diabetes, chances are your doctor has prescribed one or more oral

diabetes medications that you take on a daily basis to help control your blood glucose. Prescription medications for Type 2 diabetes lower blood sugar levels in one of two ways. Either they cause the body to release more insulin into the blood stream, or they help the body to use its own insulin more effectively.

History of Metformin

One of the oldest and most prescribed diabetes drugs in the world is metformin. Metformin is the generic name for the brands Glucophage, Glucophage XR, Fortamet, Riomet and Glumetza. The first clinical trials for metformin were published in 1957, and the drug was introduced to the UK the following year. It became available in Canada in 1972, and in 1994, metformin was finally approved for use in the U.S. for the treatment of Type 2 diabetes. 

Metformin belongs to a class of diabetes drugs called biguanides, which lower blood sugar levels by decreasing the amount of glucose the liver produces. Glucophage is the best-selling brand name of metformin and also comes in extended release form (Glucophage XR).

Metformin Dosage

Glucophage is typically taken with meals twice a day, while Glucophage XR is taken once a day, in the evening, with dinner. To prevent side effects such as upset stomach or diarrhea, your doctor will likely start you on a low dose and gradually increase the dosage until it reaches maximum effectiveness.

Metformin may also be combined with medication from other classes of diabetes drugs:

• Actomet Plus is a combination of metformin and pioglitazone
• Avandamet is a combination of metformin and rosiglitazone
• Glucovance is a combination of metformin and glyburide
• Janumet is a combination of metformin and sitagliptin
• Metaglip is a combination of metformin and glipizide

These combination medications can further decrease blood sugar levels more than either class alone.

Effectiveness of Metformin

When taken as directed, metformin by itself is highly effective. It typically lowers fasting blood sugar levels anywhere from 17% to 37%, reduces post-meal blood glucose up to 44.5% and decreases A1c levels from 0.8% to 3.1%. Taking metformin also decreases the need for Type 2 diabetics to inject insulin.

In addition, metformin helps reduce LDL cholesterol and triglyceride levels, and it is the only diabetes drug that is proven to prevent heart disease in Type 2 diabetes. When taken alone and as prescribed, metformin does not cause hypoglycemia (unlike sulfonylureas) or weight gain.

Metformin Side Effects and Precautions

Metformin should be introduced at a low dose and taken with meals to prevent bloating, gas, stomach cramps or diarrhea. Other side effects may include a metallic taste in the mouth, constipation, heartburn, headache, sneezing, cough, runny nose or skin rash.

A rare but more serious side effect called lactic acidosis, which is a buildup of lactic acid in the bloodstream, typically occurs only in those with another major health problem, such as congestive heart failure or kidney, liver or lung disease. If you have any of these conditions, you should not take metformin.

Alcohol can also trigger lactic acidosis, so if you drink more than 2 ounces of alcohol per day (approximately two alcoholic drinks), be sure to discuss this with your doctor. You should also let your doctor know if you are pregnant or breastfeeding, as he or she may substitute insulin in place of metformin while you are pregnant or lactating.

The Bottom Line

Metformin, or Glucophage, is the most popular drug of choice for the treatment of Type 2 diabetes, particularly in those who are overweight or obese. When taken as prescribed, it is extremely effective in reducing blood sugar levels and may be combined with other diabetes medications. Learn more about other classes of oral diabetes drugs >>