Health Canada has announced another metformin recall for Type 2 diabetes medications that may be contaminated with N-Nitrosodimethylamine (NDMA), a probable human carcinogen.
According to a notification posted by the regulator on March 11th, AMP Pharma Corporation is voluntarily recalling all 26 lots of its prescription metformin drug from the Canadian market (Metformin DIN 02380196 [500mg] and Metformin DIN 02380218 [850mg]) as a precautionary measure.
Athough NDMA tests results aren’t available for the affected metformin tablets, the “potential presence of nitrosamine impurities” has apparently raised concerns about their safety.
This is the third metformin recall Health Canada has announced since December, when authorities in Singapore revealed that some diabetes drugs sold there had tested positive for excessive levels of NDMA.
The first Canadian recall was announced on February 5th and involved eight lots of APO-Metformin ER (extended release) 500 mg tablets. On February 26th, Health Canada posted a second recall notice for six lots of prescription RAN-Metformin manufactured by Ranbaxy Pharmaceuticals.
The U.S. Food & Drug Administration (FDA) also began investigating reports of tainted metformin last December. While its own testing did detect NDMA in some samples, the agency ultimately concluded that the levels found were far below its daily recommended limit of 96 nanograms.
Earlier this month, however, the online pharmacy Valisure revealed that its tests had, in fact, detected excessively high levels of NDMA in 16 of 38 metformin samples tested. The highest levels were detected in tablets marketed by Amneal Pharmaceutical, which in some cases contained as much as 16-times the FDA’s recommended daily limits. Several companies’ metformin contained more than 10 times the limit.
Valisure has since petitioned the FDA for a recall of the affected metformin lots, as well as an investigation into how NDMA came to contaminate the medications.
NDMA is an environmental contaminant found in water and some foods, including processed meats. Animal studies suggest exposure to high levels of NDMA may increase the risk for cancer, especially cancers of the liver, kidneys, and gastrointestinal tract.
Last Fall, Valisure petitioned the FDA to recall Zantac and generic ranitidine products after an earlier set of tests found that the popular heart burn drugs were also contaminated with NDMA. While the agency has not yet ordered a Zantac recall, numerous manufacturers have decided to pull their ranitidine-containing medications from the market. Various retailers – including CVS, Rite-Aid, Walmart, and Walgreens – have also removed the drugs from store shelves.
In 2018, the discovery of NDMA in generic angiotensin II receptor blockers (ARBs) led drug makers around the world to recall valsartan, losartan, and irbesartan-containing heart and blood pressure medications.