The metformin recalls continue. On Monday, Nostrum Laboratories, the manufacturer, issued another recall for metformin extended-release 750mg. This is the company's second recall in 2021. On January 4, Nostrum Laboratories announced the first voluntary recall for this type 2 diabetes medication; the January recalls are considered an expansion of one announced November 2 by the same company. Both January recalls were for the same product, Metformin HCl extended release tablets, USP 750.

As of January 25, there have been no announcements regarding illnesses connected to the recalled product.

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. The lot number for the January 25 recall is MET2006010; the expiration date is July 2022

Metformin controls blood glucose levels, together with diet and exercise. As to the long-term effects of exposure to NDMA, the FDA told Medical Daily earlier this month 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.

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.

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.