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  1. Drug Safety and Availability

FDA Updates and Press Announcements on NDMA in Metformin

Nitrosamine Impurities in Medications


[2/3/2020] The U.S. Food and Drug Administration posted laboratory results showing N- Nitrosodimethylamine (NDMA) levels in some metformin products approved in the U.S. FDA has determined that the levels of NDMA in metformin products tested range from not detectable to low levels. To date, no sample of metformin that FDA has tested exceeds the acceptable daily intake for NDMA. FDA has not recommended metformin recalls in the U.S.

Metformin is a prescription drug used to control high blood sugar in patients with type 2 diabetes. Patients should continue taking metformin to keep their diabetes under control. It could be dangerous for patients with this serious condition to stop taking their metformin without first talking to their health care professionals.

FDA plans to post the methods used in laboratory testing of metformin in the near future. FDA is also collaborating with international regulators to share testing results for metformin, along with testing results for other drugs.

FDA will continue to monitor NDMA in metformin, along with other drugs products, and will provide timely updates of new developments, including product recalls. For more information about NDMA, visit FDA’s nitrosamines webpage

FDA encourages health care professionals and patients to report adverse reactions or quality problems with any human drugs to the agency’s MedWatch Adverse Event Reporting program:

FDA-published testing method to provide an option for regulators and industry to detect NDMA impurities
The link below is to an FDA-published testing method to provide an option for regulators and industry to detect nitrosamine impurities in metformin drug substances and drug products. This method should be validated by the user if the resulting data are used to support a required quality assessment of the API or drug product, or if the results are used in a regulatory submission.
  • LC-HRMS method: an LC-MS method for the detection of NDMA in metformin drug substance and drug products.
  • Additional test methods will be posted when available.