Metformin is not new. Made from a perennial herb called Galega officinalis, it was first created in 1929. In 1972, Health Canada approved the use of metformin, and made it available to Canadians.

How does it work?

Metformin works in several ways. Some of the exact effects are still being researched. We know it acts on the liver, increasing the liver’s sensitivity to glucose. It signals the liver to stop adding more glucose to the blood. It also lowers the amount of blood glucose by increasing the uptake of glucose by the muscles, and slowing absorption of glucose from the gastrointestinal system after you eat.

How do I take metformin?

Metformin can be taken with or without food. Taking it with a meal is suggested, as this reduces the chance of some side effects. Usually metformin is taken twice a day. Maximum recommended doses of around 2550 milligrams a day are not uncommon. If you forget a dose of metformin, take your next dose as scheduled. Do not double up on the next dose as this could lead to side effects.

What are the common side effects of metformin?

The main side effects are nausea, vomiting, and diarrhea. Taking the medication with food, right before or right after you eat, can greatly reduce these effects. However, missing a meal does not mean you should skip your metformin dose.

To reduce side effects when you first begin taking metformin, start with a low dose and slowly increase it every few days as tolerated. You may need to begin with only half a tablet twice a day, and then slowly increase to the full dose prescribed by your doctor.

How Metformin Works

We know metformin acts on the liver, increasing the liver’s sensitivity to glucose. It signals the liver to stop adding more glucose to the blood. It also lowers the amount
of blood glucose by increasing
the uptake of glucose by the muscles, and slowing absorption of glucose from the gastrointestinal system after you eat.

Will metformin make my blood glucose go too low?

Metformin alone should not cause hypoglycemia (low blood glucose) or a sudden drop of your blood glucose level. It does not make your body release more insulin. Instead, it deals with how your body uses glucose.

Is it safe to take metformin with my insulin or other medications?

Yes, if your doctor or another health care provider instructs you to do so. Metformin can actually increase the effect of insulin and make it work better. Other oral anti-diabetic medications work by a different mechanism and are usually safe to take as well. Overall, metformin has very few interactions with other drugs.

Can metformin really lower my level of vitamin B12?

Your doctor may send you for a blood test every year or two to check your vitamin B12 level. During clinical trials to study metformin, only seven per cent of patients had reduced B12 levels. Once they stopped taking metformin, B12 levels rapidly returned to normal. Taking vitamin B12 supplements is an option.

Will metformin make me gain weight?

Unlike other oral diabetes medications, metformin has been shown to be ‘weight neutral.’ This means you should not gain weight because you are taking it. In some people metformin modestly reduces weight. This reduction is usually quite stable. Those who continue to take metformin as directed do not regain the weight.

Other interesting benefits

Another benefit of metformin is its cost. The drug has been available as a generic since 2002. It is one of the least expensive diabetes medications. Metformin also appears to lower the risk of heart disease, a common complication of diabetes. The risk of certain cancers is also reduced in people with type 2 diabetes who take metformin. Exactly how this occurs is not known and is still being studied.

Research is finding more benefits to this drug aside from lowering blood glucose. It is now being used more widely. It can help certain people with type 1 diabetes who are resistant to insulin, and those with polycystic ovary syndrome (PCOS) and impaired glucose tolerance.

Overall, metformin has been continually a safe and tolerable medication. It has stood the test of time, and continues to be valuable in treating diabetes.

Metformin Answers to frequently asked questions