The FDA vowed to protect patients, and to focus its efforts on maintaining “strict quality standards” in a public statement released Friday that addressed the impurities recently found in some drugs. Janet Woodcock, MD and director of FDA’s Center for Drug Evaluation and Research also addressed recent concerns about metformin, used to treat diabetes.

Several drug products, including angiotensin II receptor blockers and ranitidine, have been found to contain small amounts of nitrosamines, such as N-Nitrosodimethylamine (NDMA), over the past year and a half, and the FDA has been investigating these issues. NDMA is classified as a probable human carcinogen, and is a known environmental contaminant.

Other countries have reported to low levels of NDMA in metformin. However, these levels are within the range that is naturally occurring in some foods and water, according to Woodcock.

“While we are aware that some regulatory agencies outside the US may be recalling some metformin drugs, there are no metformin recalls affecting the US market at this time,” Woodcock said in the prepared statement. “The FDA is investigating whether metformin in the US market contains NDMA, and whether it is above the acceptable daily intake limit of 96 nanograms.”

The FDA recommends that prescribers continue to use metformin when clinically appropriate, as the investigation is ongoing, since stopping use of the drug could be dangerous for some patients. There are currently no alternative medications that similarly treat this condition, according to the agency.

NDMA is a common contaminant found in water and foods, including cured and grilled meats, dairy products, and vegetables, which puts everyone at exposure to some level of NDMA. According to the FDA, the acceptable daily intake limit for NDMA in the US is 96 nanograms. The levels of NDMA should not be something to worry about, according to Woodcock.

“Today, we have better testing methods than ever before, and we know what to look for in products’ chemical structure, and manufacturing processes that may increase the risk of forming low levels of nitrosamines,” Woodcock said. “Improved technology enables us to detect even trace amounts of impurities in drug products and may be the reason why more products have been found to have low levels of NDMA.”

The FDA will continue to investigate the source of these impurities, following their “strict standards for safety, effectiveness, and quality,” and working closely with international drug regulatory agencies to leverage resources and test outside of the US. In previous findings, the FDA has found the source of NDMA related to the drug’s manufacturing process, chemical structure, or conditions in how they are stored or packaged. The sources for the several drugs possibly containing NDMA will continue to be tested and researched.

“Protecting patients is the FDA’s highest priority, and Americans can be confident in the quality of the products the agency approves,” Woodcock said. “We are patients too, and we’re committed to maintaining our high standards for quality, safety, and efficacy for all drugs we, our families, friends, colleagues, and millions of fellow Americans rely on for their health.”

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REFERENCE

Statement from Janet Woodcock, MD, director of FDA’s Center for Drug Evaluation and Research, on impurities found in diabetes drugs outside of US [news release]. Silver Spring, MD; FDA: December 5, 2019. https://www.fda.gov/news-events/press-announcements/statement-janet-woodcock-md-director-fdas-center-drug-evaluation-and-research-impurities-found. Accessed December 6, 2019.