The FDA has issued yet another recall of metformin extended-release tablets. On January 4, Nostrum Laboratories announced a voluntary recall for this type 2 diabetes medication; this latest recall is an expansion of one announced November 2 by the same company. The recall is for one lot of metformin HC1 extended-release tablets, 750mg.
As with the other metformin recalls, which so far have involved at least eight companies, the pills were found to contain nitrosamine impurities. N-Nitrosodimethylamine (NDMA) is a suspected human carcinogen. The recalls began in June. Medical Daily reported in November that the FDA has asked metformin manufacturers and distributors to test all lots coming in from overseas. The FDA said at the time that the numerous recalls could be due to the drug’s manufacturing process, the drug’s chemical makeup or to new FDA technology capable of detecting tiny amounts of impurities.
No one has gotten sick from the contaminated metformin. Metformin treats type 2 diabetes by controlling blood glucose levels, together with diet and exercise. As to the long-term effects of exposure to NDMA, the FDA told Medical Daily this week that the agency did not know how long patients were exposed to the contaminated medication, “but we do not anticipate that shorter term exposure at levels above the acceptable intake limit would lead to an increase in the risk of cancer,” the agency wrote in an email.
NDMA-contaminated medications for other medical conditions have been recalled as well. Drugs such as valsartan, losartan and irbesartan, which widen blood vessels to treat those with high blood pressure, have been recalled. In April 2020, ranitidine, an antihistamine and antacid sold as Zantac was removed from stores after the FDA requested it. The agency alerted consumers to this contaminated product in September 2019. Also in April 2020, a similar medication, nizatidine, also was recalled. Recalls of the blood pressure medications date back to 2018.
As for preventing more recalls of metformin, “The agency is asking all manufacturers of extended-release versions of metformin to evaluate their risk of excessive NDMA and to test at-risk product before each batch is released onto the U.S. market,” said the agency.
In September 2020, the FDA also released guidelines for industry to help manufacturers be aware of sources of NDMA contamination and to stop contaminated drugs from reaching the market by testing, monitoring and changing manufacturing practices.