Decades strong: is this age-old medicine still relevant in diabetes management?

What is Metformin?

Metformin is commonly prescribed to people with type 2 diabetes, but sometimes doctors use it for other conditions too, like polycystic ovary syndrome (PCOS) and prediabetes.

There are several brands of Metformin available including:

How does Metformin work?

When you eat carbohydrate containing food, your body breaks it down into sugar (glucose), which is then used for energy. In diabetes, there's too much glucose in the blood. This is because either insulin is not being produced (Type 1 diabetes) or the body is not using insulin well and there is not enough insulin being produced (Type 2 diabetes). That's where Metformin comes in.
Metformin works in a few ways:

1. Liver control: It stops the liver from releasing too much glucose into the bloodstream. The liver is like a warehouse in our body. Normally, it stores and releases glucose to keep our energy levels steady during times of fasting. When you have type 2 diabetes, the liver can make too much glucose. Metformin helps to dial down this production, keeping glucose levels in balance.
2. Increases insulin sensitivity: It helps muscles and fat cells become more sensitive to insulin, which helps the cells use glucose more easily.
3. Appetite management: It can also help some people to feel less hungry. This can be helpful in managing weight, which can be another important aspect of managing diabetes.

How is Metformin taken?

The size of Metformin tablets are on the larger side when it comes to diabetes tablets. It's typically taken with meals to help reduce stomach upset, which can be a side effect for some people. Doctors usually start with a low dose such as 250mg or 500mg and gradually increase it as needed to get blood glucose levels within target range. The standard dose of Metformin tends to be 1g or 1000mg to 2g or 2000mg daily.

Is Metformin safe?

Metformin has been around for a long time, so it has been well studied. For most people, Metformin is safe and well-tolerated, but like any medicine, it can have side effects. Common side effects include upset stomach and diarrhea. These side effects are usually mild and go away on their own. This is why it’s recommended to start on a low dose and gradually increase to give your body time to adjust. It’s also recommended to take Metformin with food to help avoid or reduce stomach upset.

In some cases, it can also cause vitamin B12 deficiency if taken for a long time.

Rarely, Metformin can cause more serious side effects like lactic acidosis which is a build-up of a substance called lactic acid in the blood. This is very rare and mostly occurs in people with kidney problems or other serious health issues.
It’s also important to note that Metformin should be stopped 48 hours before any major elective surgery. Major surgery usually means any surgical procedure where you would need an overnight stay at the hospital. Speak to your health care team for more information on when to stop and re start Metformin to avoid serious complications.

What to do if you're not tolerating Metformin

If you're taking Metformin and experiencing side effects that you find difficult to live with, it's important to talk to your healthcare team. They can help figure out whether the side effects are temporary and if they might lessen over time as your body adjusts to the medication. In some cases, adjusting the dose, changing the timing of when you take the medication, or switching to a different form of metformin (such as an extended-release version) may help with side effects. Alternatively, you can speak with your GP or Diabetes Nurse Educator about other treatment options that might be appropriate for you.

Additional benefits of Metformin

Metformin has shown promise in addressing other health conditions beyond diabetes. Here are some potential benefits:

• Polycystic Ovary Syndrome (PCOS): Metformin is commonly prescribed for women with PCOS to help regulate menstrual cycles and improve fertility by addressing insulin resistance, a common feature of PCOS.

• Weight management: Some studies suggest that metformin may aid in weight loss or weight maintenance, particularly in individuals with obesity or those at risk of developing diabetes.

• Heart health: Research indicates that metformin may have beneficial effects on cardiovascular health by improving lipid profiles, reducing inflammation, and potentially lowering the risk of heart disease in people with diabetes.

• Cancer prevention: There's ongoing research exploring the potential role of metformin in cancer prevention and treatment, particularly in cancers such as breast, colon, and prostate cancer, due to its effects on cell growth and metabolism.

• Longevity: Some studies suggest that metformin may have a positive impact on lifespan and age-related diseases, leading to interest in its potential as an anti-aging medication. However, more research is needed to fully understand its effects on longevity in humans.

While these potential benefits are promising, it's important to consult with a healthcare team before using Metformin for conditions other than diabetes to ensure safe and appropriate use.

Recalls and safety concerns

A few years ago, there were concerns about certain batches of Metformin being recalled in the United States. This happened because some batches were found to contain higher than acceptable levels of a substance called N-Nitrosodimethylamine (NDMA), which is considered a probable human carcinogen. NDMA is not an ingredient in Metformin; it's a contaminant that can form during the manufacturing process.

The Therapeutic Goods Administration (TGA), Australia's regulatory body for therapeutic goods, closely monitors the safety and quality of medications available in the country. Australian Metformin products undergo rigorous testing and quality control measures to ensure they meet strict safety standards before being made available to patients. They stated that the risks from not treating diabetes are far greater than the risks posed by the levels of NDMA seen to date in Australian manufactured Metformin. You can read more on this topic here.

Metformin is a valuable tool we have available in our diabetes management toolbox. Although it’s getting on in years and there has been the introduction of several other classes of diabetes medications, it’s still the number one option for many people living with type 2 diabetes.

If you’re interested in having a diabetes medication review, book an appointment with your GP or Credentialed Diabetes Nurse Educator at the Diabetes Victoria Clinic.