The online pharmacy, Valisure, found that batches of the metformin diabetes medicine made by nearly a dozen companies after contains excessive amounts of the possible carcinogen, NDMA – the same harmful ingredient that has also led to recalls of heartburn and blood pressure medication.  Metformin is used to control high blood sugar levels in people with Type 2 diabetes.In a petition filed with the Food and Drug Administration (FDA), Valisure stated that “independent laboratory testing detected NDMA above the daily acceptable intake level in 16 batches of the diabetes treatment made by 11 different manufacturers.”  The company also found many of the batches “contained more than 10 times the acceptable limit.”NDMA is an organic chemical that was once used to make rocket fuel and is a byproduct of certain chemical reactions.  The United State Environmental Protection Agency (EPA) and the World Health Organization (WHO) consider it to be potentially cancer-causing.

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“The presence of this probable carcinogen in a medication that is taken daily by adults and adolescents for a chronic condition like diabetes makes this finding particularly troubling,” Valisure wrote.  However, it noted, its findings “may be primarily due to contamination during manufacturing as opposed to a fundamental instability of the drug molecule.”The FDA recently posted lab results showing levels of NDMA in some versions of metformin, but the agency said the amount of NDMA ranged from not detectable to low.  At the time, the FDA found that “no sample it tested exceeded” what it says is “an acceptable daily intake for NDMA,” and, as a result, has not recommended manufacturers recall metformin from the U.S.The FDA has claimed exposure to 96 mg of NDMA per day is reasonably safe.  Lifetime exposure may increase the risk of cancer, “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.”“Valisure urges FDA and industry to take swift and broad action to clean up the U.S. supply of metformin, a drug that tens of millions of Americans rely on,” Valisure chief executive officer David Light said. “Valisure’s results indicate that contaminated batches of drugs are scattered and intermixed with clean ones throughout the American pharmaceutical supply chain…This strongly suggests that neither the limited testing FDA is able to conduct, nor the pharmaceutical companies’ self-reporting of analytical results is sufficient, to protect American consumers from potentially dangerous contamination in the U.S. drug supply.  Independent, third-party analysis of medication taken direct from pharmacy supply is needed more than ever.”Light added, “This certainly underscores the prevalence of existing pharma quality problems, which may end up becoming even worse as coronavirus continues to derail Chinese drug manufacturing, where the majority of U.S. drugs originate from.  Many of these existing safety and quality issues, like the ones we identified in metformin, likely stem from overseas manufacturers cutting corners.  It is certainly possible that many more corners may be cut in the scramble to ramp up production and fill backorders.”Last December, the Health Sciences Authority in Singapore announced traces of NDMA were found in some metformin pills “above acceptable levels” and began “a precautionary measure to recall three of the 46 marketed pills that were tested.”  Health Canada has since asked two companies to recall their products and the European Medicines Agency asked manufacturers to test theirs as well.In fall 2019, Valisure filed a similar petition with the FDA after finding NDMA in heartburn pills under such brand names as Zantac. The disclosure prompted regulators to ask companies to test their medications and led to mass recalls all over the world.

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FDA petitioned to recall batches of metformin diabetes pill over a possible carcinogenTesting lab challenges FDA findings that carcinogens in metformin do not exceed acceptable levels