FDA Finds High Levels of Carcinogen in Extended-Release Metformin

May 28, 2020

Months after FDA said it was investigating the carcinogenic ingredient NDMA in metformin products, the agency’s testing has found elevated levels of NDMA in extended release metformin, but not in the immediate release formulation. 

Months after FDA said it was investigating the carcinogenic ingredient N-Nitrosodimethylamine (NDMA) in metformin products, the agency’s testing has found elevated levels of NDMA in extended release (ER) metformin but not in the immediate release (IR) formulation, FDA said in a statement issued to FormularyWatch.

Although 

some news reports

 said a recall of extended release metformin products is imminent, FDA told 

FormularyWatch

 that it “cannot confirm or deny a recall action before it has taken place.”   The agency’s testing found that “certain extended release metformin products contain NDMA above the acceptable level,” FDA said.

“FDA is contacting companies with ER metformin above the acceptable level and will continue to take quick and appropriate action when needed to protect American consumers. We are committed to providing timely updates on our investigations and any recalls,” FDA said.

The FDA said that patients should not stop taking their prescription medications without first talking to their health care providers. In early February, the agency posted the results of its laboratory analysis showing NDMA levels in some samples of the metformin products it tested. Overall, the levels of NDMA found in metformin ranged from “not detectable to low levels” at the time.

According to the agency, no sample of metformin that was tested by the FDA exceeded the acceptable daily intake of NDMA. In December, regulatory agencies outside of the United States recalled some metformin drugs due to low levels of the impurity, prompting FDA officials to test samples of metformin sold in the United States.

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