Nitrosamine Impurities Trace in Metformin

Metformin is a prescription drug used to control high blood sugar in patients with type 2 diabetes. The Regulatory agency announced that traces of Nitrosamine are present in generic drug substances and drug products, further FDA and EMA investigation also led to the detection of these Nitrosamine impurities in low levels of NDMA impurity in Metformin.

Recent investigation:

FDA has been investigating the presence of nitrosamines in drug products and in late 2019, become aware of NDMA in some Metformin products in other countries. The regulatory agency started testing to determine whether the Metformin in the U.S. supply was at risk, as part of the ongoing investigation into nitrosamine impurities across medication types. In February 2020, they identified very low levels of NDMA in some samples, but at that time, no FDA-tested sample of Metformin exceeded the acceptable intake limit for NDMA. The FDA has maintained that it would continue with ongoing testing of Metformin and other medications, and if any levels of NDMA or other impurities were identified, swift action would be taken. Recently FDA became aware of reports of higher levels of NDMA in certain extended-release (ER) formulations of  Metformin.

In addition, EMA and national authorities are also assessing the impact of recent tests that found NDMA in some EU batches of Metformin medicines, used for diabetes. Further results from tests on Metformin in the EU are being awaited. In line with previous advice, patients should continue taking their Metformin medicines as usual. The risk of not having adequate diabetes treatment far outweighs possible risks from low levels of nitrosamines.

As Metformin is considered a critical medicine, EMA and national authorities are cooperating closely to avoid possible shortages so patients can continue to get the treatments they need

Lab testing for the analysis of NDMA in metformin

FDA continues to investigate the presence of the N-Nitrosodimethylamine (NDMA) impurity in Metformin approved for sale in the U.S. Metformin is a prescription drug used to control high blood sugar in patients with type 2 diabetes. FDA testing has found NDMA in certain lots of extended-release (ER) Metformin and is recommending companies recall lots with levels of NDMA above the acceptable intake limit of 96 nanograms per day. FDA is also collaborating with international regulators to share testing results for Metformin. For reference, consuming up to the acceptable daily intake limit, 0.096 micrograms (96 nanograms), of NDMA per day is considered reasonably safe for human ingestion based on lifetime exposure. NDMA may increase the risk of cancer if people are exposed to it above the acceptable level and over a long period of time, but a person taking a drug that contains NDMA at or below the acceptable daily intake limit every day for 70 years is not expected to have an increased risk of cancer

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  • FDA alerts on nitrosamine impurity findings in metformin, available at
  • European medicines agency, available at
  • Laboratory analysis of metformin products, available at

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