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TGA investigation - potential contamination with N-nitrosodimethylamine

12 December 2019

Update: 18 November 2020

The TGA has published further information about this issue, including outcomes of laboratory testing of Australian metformin products.

The TGA is aware that some overseas regulators have detected low levels of N-nitrosodimethylamine (NDMA) in a small number of metformin products.

Metformin, which is marketed in Australia under multiple trade names, is a prescription medicine used to treat type 2 diabetes.

It has not yet been confirmed that NDMA is present in any metformin products supplied in Australia. The TGA is working with other international regulators and medicine sponsors to further investigate this issue and determine what actions may be required.

It is critical that patients do not stop taking their metformin medicines unless instructed to by their health professional.

What is NDMA?

NDMA is a type of N-nitroso compound. N-nitroso compounds are commonly found in low levels in a variety of foods, particularly smoked and cured meats, as well as in some drinking water and in air pollution. Long-term exposure, over many years, can increase an individual's risk of developing cancer.

The additional risk that would be posed by any potential trace levels of NDMA being detected in metformin is considered to be very low.

The TGA has also been investigating NDMA and other N-nitroso compounds that have been found in 'sartan' blood pressure medicines and ranitidine products.

What should consumers do?

Please be aware that it has not yet been confirmed that NDMA is present in any metformin products supplied in Australia. It is also important to note that even if NDMA is detected in some Australian products, it is likely that not all products or all batches will be affected.

If you take metformin, do not stop your treatment without first consulting a doctor or pharmacist. It is very important to keep diabetes under control and stopping your diabetes medicines poses a greater and more immediate risk to health than potential low-level contamination with NDMA.

Complications associated with uncontrolled diabetes include heart disease, nerve problems, kidney damage, eye problems and damage to the foot that can lead to amputations. If you have any questions or concerns about this issue, you should speak to your health professional.

What should health professionals do?

Please be aware of this potential issue and advise patients accordingly.

There is no reason to stop prescribing metformin. It has not yet been confirmed that NDMA is present in any metformin products supplied in Australia.

You may wish to remind patients of the importance of keeping diabetes under control and reassure them that that the risks posed by NDMA at the trace levels observed overseas are considered very low.

What is the TGA doing?

The TGA has required all Australian sponsors of metformin medicines to undertake testing of their products and to report the results to us.

The TGA recognises the important role of metformin in managing diabetes in Australia. Therefore, any regulatory action will take into consideration the need to ensure continued availability of metformin in the interest of public health.

The TGA will publish updated information, as appropriate, when it becomes available.

Reporting problems

Consumers and health professionals are encouraged to report problems with medicines or vaccines. Your report will contribute to the TGA's monitoring of these products.

The TGA cannot give advice about an individual's medical condition. You are strongly encouraged to talk with a health professional if you are concerned about a possible adverse event associated with a medicine or vaccine.