The Food and Drug Administration is testing the popular diabetes drug metformin for levels of possible cancer-causing chemicals.
Metformin, a prescription drug used to control high blood sugar in patients with type 2 diabetes, is just the latest medication suspected to contain the carcinogen N-nitrosodimethylamine (NDMA). Over the past 18 months, some high blood pressure and heartburn medications have been recalled for containing NDMA.
Janet Woodcock, director of FDA’s Center for Drug Evaluation and Research, said the FDA is investigating whether metformin in the United States contains NDMA, and whether it exceeds the acceptable daily limit of 96 nanograms. Though other countries have recalled the drug, no such recalls affect the U.S. market at the moment.
“The agency will also work with companies to test samples of metformin sold in the U.S. and will recommend recalls as appropriate if high levels of NDMA are found,” Woodcock said in an agency statement.
She cited several reasons why impurities can be present in drugs, including manufacturing processes or even the conditions in which they are packaged or stored. “If as part of our investigation, metformin drugs are recalled, the FDA will provide timely updates to patients and health care professionals,” she said.
While the FDA investigates metformin, the agency recommends doctors continue prescribing and patients  continue taking the medication. “It could be dangerous for patients with this serious condition to stop taking their metformin without first talking to their health care professional,” Woodcock said.
