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FDA testing metformin for traces of nitrosamines

MHRA aware of issue and advises patients to continue to taking their diabetes medicine

Ingrid Torjesen

Tuesday, 10 December 2019

The US Food and Drug Administration (FDA) has announced that it is testing metformin in the US for traces of nitrosamines because it is aware that some regulatory agencies outside the U.S. may be recalling some metformin drugs due to the presence of these contaminants.

Over the past 18 months, several drug products including angiotensin II receptor blockers (ARBs) and ranitidine, commonly known as Zantac, have been found to contain small amounts of nitrosamines such as N-Nitrosodimethylamine (NDMA), and there has been an ongoing investigation into the presence of nitrosamines in other drug products.

Janet Woodcock, director of the Center for Drug Evaluation and Research at the FDA said: “The FDA is aware that some metformin diabetes medicines in other countries were reported to have low levels of NDMA. Based on the information we have available, the levels of NDMA seen outside the U.S. are within the range that is naturally occurring in some foods and in water. While we are aware that some regulatory agencies outside the U.S. may be recalling some metformin drugs, there are no metformin recalls affecting the U.S. market at this time. The FDA is investigating whether metformin in the U.S. market contains NDMA, and whether it is above the acceptable daily intake limit of 96 nanograms.”

The Medicines and Healthcare products Regulatory Agency (MHRA) says that it is aware of the issue and has advised patients in the UK to continue taking their metformin medicines as usual because the risks from not having adequate diabetes treatment far outweigh any possible effects of the low levels of NDMA seen in metformin medicines outside the UK.

The levels of NDMA seen in the affected non-UK metformin medicines are very low and appear to be within or even below the range that people would normally be exposed from other sources, including food and water, the MHRA emphasises.

As these metformin medicines are also available in Europe and outside the EU, the MHRA is working closely with the European Medicines Agency (EMA) and other regulatory authorities to determine whether any further action is required.

Last year the EMA started a review of ranitidine medicines and launched a procedure to request companies to take specific measures to avoid the presence of nitrosamines in human medicines, including metformin.

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