Biguanides Medications: Benefits and Side Effects

Publish On Type 2 Diabetes By Sandra Wilson

Biguanides Medications Benefits and Side Effects

What are Biguanides Drugs?

Biguanides (such as generic metformin) are a class of oral medications for people with pre-diabetes, type 2 diabetes, and polycystic ovarian syndrome. Biguanides, like metformin, work by boosting the amount of sugar absorbed by your body’s cells. It also lowers the amount of sugar produced by the liver and reduces your body’s need for insulin.

Along with a healthy diet and exercise, biguanide medications can be taken on their own or as part of a combination medication to regulate blood sugar. Unless it is taken with other medications, metformin is unlikely to cause low blood sugar (hypoglycemia), and it does not cause the pancreas to make more insulin.

The brand name for metformin is Glucophage. A liquid version of this medication is called Riomet, and long-acting brands are called Glucophage XR, Glumetza and Fortamet.

Metformin is available in the following combination pills:

Before taking a biguanide medication, there are a few things you should know…

Taking metformin causes some people to lose weight.

There are special considerations for women considering taking a biguanide. If you no longer menstruate, biguanide drugs may cause you to begin menstruating again. This means you can also become pregnant while taking metformin, even if you are taking an oral contraceptive.

It is not known whether biguanides pass through breast milk, or whether the medication can affect your unborn baby. So if you are pregnant or breastfeeding, you should tell your doctor before taking a biguanide.

It is also a good idea to let your doctor know about any other products you currently use, including prescriptions and over-the-counter remedies, like vitamins and herbal supplements, to guarantee that they are safe to use in conjunction with metformin.

Biguanides Side Effects 

As with any medication, biguanides may cause some side effects. Some of these effects can be serious in nature, so if you suffer from any of the following symptoms you should tell your doctor or health care provider:

  • Hives
  • Lactic acidosis

If you have kidney or liver failure, have low amounts of oxygen in your blood (hypoxia), have a severe infection, are dehydrated, or drink alcohol, you may experience lactic acidosis. It can also occur if you have undergone a medical procedure, like certain surgeries or x-rays, that used a dye. If you need a test involving a dye, you should tell your doctor. You may need to temporarily stop taking metformin.

Symptoms of lactic acidosis include

  • rapid breathing
  • heavy sweating
  • clammy skin
  • confusion
  • stomach pains
  • nausea 
  • vomiting
  • Severe allergic reactions

Some people may suffer an allergic reaction to biguanide medications. If at any time you experience trouble breathing, chest pains, swelling of your face, lips, tongue or throat, stop taking your medication right away and get emergency medical attention.

The most common side effects include

  • nausea
  • diarrhea
  • decreased appetite
  • increased gas
  • metallic taste in your mouth.

These mild side effects do not usually require medical attention and should fade as your body adjusts to the medication. Often your doctor will start you on a lower dose, and gradually increase as you adjust to the side effects. You may have less chance of experiencing nausea if you take metformin with food.

If taken over a period of years, metformin may lower your levels of vitamin B12. The symptoms of type 2 diabetes can worsen over time, so it is a good idea to book regular check-ups and blood tests in case your dose or medication needs to be changed.

Taking biguanide medications can help keep your blood sugar in a healthy range and reduce your risk of any long-term complications associated with type 2 diabetes.

Disclaimer: Please note that the contents of this community article are strictly for informational purposes and should not be considered as medical advice. This article, and other community articles, are not written or reviewed for medical validity by Canadian Insulin or its staff. All views and opinions expressed by the contributing authors are not endorsed by Canadian Insulin. Always consult a medical professional for medical advice, diagnosis, and treatment.