Posted on: June 9, 2020 at 4:58 pm

Five U.S. drugmakers are recalling their versions of metformin, a widely-used diabetes medication, that has been found to have high levels of the chemical N-Nitrosodimethylamine (NDMA), which is linked to cancer [1].


What is Metformin?

Metformin is a very common medication used to lower the blood sugar levels in individuals with type II diabetes. It is often described as an insulin sensitizer, because it helps to decrease insulin resistance in patients with type II diabetes, and is typically the drug of choice for obese individuals with the disease because it can help with modest weight loss [2].

What is NDMA?

NDMA occurs through the degradation of dimethylhydrazine, which is a component of rocket fuel, as well as from other industrial processes. It has been proven to be a potent carcinogen in animals and is therefore classified as Group 2A, probably carcinogenic to humans, by the International Agency for Research on Cancer (IARC) [3].


NDMA does not persist in the environment because it breaks down when exposed to sunlight in a matter of minutes. If it ends up in the soil, it can either evaporate from its surface and breakdown from UV exposure or it can penetrate deep into the ground and take a few months to break down. The rate of degradation in water is not known [4].

Where is NDMA Coming From?

NDMA is all around us, and we are exposed to it through many sources.

Humans can be exposed to the contaminant through tobacco smoke, chewing tobacco, diet [cured meats (particularly bacon), beer, fish, cheese, and other food items], toiletry and cosmetic products (for example, shampoos and cleansers), interior air of cars, and various other household goods, such as detergents and pesticides [4].

NDMA can enter the body when a person breathes contaminated air, drinks contaminated water, or consumes a contaminated food item [4].


But how is the contaminant ending up in medications? The answer is that it depends on the drug. According to the FDA, the source can be related to the drug’s manufacturing processes, or the conditions under which the drug is stored and packaged.

David Light, the CEO of Vasilure, explains that NDMA is made up of two parts: The N (nitroso group), and the DMA (dimethylamine). In order for NDMA to form, you have to have both parts. Some drugs have both components in their structures, while others do not [5].

“That explains a little bit why we saw NDMA in varying levels, even in the same drug from the same manufacturer,” said Janet Woodcock, the director of the FDA’s Center for Drug Evaluation and Research [5].

This high degree of variability is what makes it difficult to determine the source of contamination for each drug. Manufacturers must figure out whether the contamination is coming from within the drug itself, or if it’s from the packaging or processing of the medication [5].

Read: 7 Fruits to Avoid If You Have Diabetes

The Metformin Recall

In early May, the FDA alerted patients and healthcare professionals that five companies voluntarily recalled certain extended release (ER) drugs. As per the FDA’s statement, these companies are recalling their ER drugs:

  • Apotex – All lots
  • Teva – All lots
  • Amneal – All lots
  • Marksans – One lot (XP9004)
  • Lupin – TBD [6]

The statement noted that there are other manufacturers of the drug whose products are not being recalled at this time. They are recommending that patients who are in possession of the recalled medications continue taking them until their doctor or pharmacist is able to get them a replacement, since it can be very dangerous for patients with type II diabetes to stop taking their metformin [6].

Read: Scientists Have Successfully Cured Diabetes in Mice for the First Time

Was COVID-19 Behind This?

The FDA is responsible for ensuring that any medicines made for the US market are made in safe, sanitary conditions, and that the drugs meet federal quality standards. The agency suspended nearly all US and foreign inspections in March, however, due to safety concerns and travel restrictions put in place by the COVID-19 global pandemic.

Government inspectors have also been criticised in the past for doing an inadequate job at reviewing overseas manufacturing plants as the pharmaceutical industry has increasingly spread to Asia [1].

Regulators are still assessing whether or not the recalls will result in a shortage of the crucial diabetes medication, however, they note that a number of other companies make generic brands that have not been affected [1].

This is not the first time Metformin has been recalled over contamination fear, nor is it the first drug to be recalled due to NDMA contamination. It has also been found in some heartburn medications, as well as blood pressure and heart failure drugs.

Keep Reading: An oral insulin capsule passed second stage testing for efficacy and safety, paving the way to diabetes treatments without shots.
Brittany Hambleton
Team Writer
Brittany is a freelance writer and editor with a Bachelor of Science in Foods and Nutrition and a writer’s certificate from the University of Western Ontario. She enjoyed a stint as a personal trainer and is an avid runner. Brittany loves to combine running and traveling, and has run numerous races across North America and Europe. She also loves chocolate more than anything else… the darker, the better!

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