The U.S. Food & Drug Administration(FDA) is working to determine if metformin, a widely used diabetes drug, is contaminated with N-nitrosodimethylamine (NDMA), the same chemical that triggered multiple Zantac recalls earlier this year.
According to Reuters, the FDA launched this latest investigation after regulators in Singapore recalled three metformin products for the presence of NDMA. The European Medicines Agency has since asked drug makers to test metformin medicines sold in the European Union, and regulators in Canada are also looking into the matter.
Metformin is a standard treatment for Type 2 diabetes. It is sold under a number of brand names, including Fortamet and Glucophage, as well as generic versions.
“The FDA is investigating whether metformin in the U.S. market contains NDMA, and whether it is above the acceptable daily intake limit of 96 nanograms,” Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research, said in statement issued on December 5th.
The agency indicated it would announce metformin recalls “as appropriate if high levels of NDMA are found.”
Patients should continue taking metformin to control their diabetes, as stopping treatment without first talking to their doctor could be extremely dangerous for these individuals. Healthcare providers should also continue to prescribe metformin, as there are no alternative medications that treat Type 2 diabetes in the same way.
The U.S. Environmental Protection Agency (EPA) has designated NDMA a probable human carcinogen, as exposure above acceptable limits for long periods of time may increase the risk of certain cancers.
Earlier this year, the FDA warned that unacceptable levels of NDMA had been detected in generic and name-brand versions of Zantac (ranitidine), a popular heartburn medication. The agency learned of the contamination from Valisure, an online pharmacy that apparently found NDMA in every sample of ranitidine and Zantac it tested, and often at levels that greatly exceeded the FDA’s acceptable daily limit of 96 nanograms.
Valisure believes the NDMA in Zantac resulted from the instability of the ranitidine molecule, which purportedly degrades when subjected to conditions similar to digestion. However, the FDA has yet to determine if ranitidine actually produces NDMA in the stomach.
While the FDA hasn’t ordered any Zantac recalls, various drug makers have opted to pull their products from the market and some retailers have stopped selling ranitidine-containing heart burn medications.
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.