After Zantac scare, FDA targets generic metformin for carcinogen tests

After a global scare over carcinogen contamination in heartburn med Zantac, regulators are growing increasingly wary about other drugs that may have flown under the radar. Now, generic metformin, a Type 2 diabetes medication, could be next in the FDA's firing line. 

The FDA is testing samples of metformin for the probable carcinogen N-nitrosodimethylamine (NDMA) that has already been tied to global recalls of generic and branded Zantac earlier this year and for "sartan"-based heart pressure drugs in 2018. 

"The agency is in the beginning stages of testing metformin; however, the agency has not confirmed if NDMA in metformin is above the acceptable daily intake (ADI) limit of 96 nanograms in the U.S.," FDA spokesman Jeremy Kahn said in an email. "These investigations take time. The FDA will communicate further information when we understand more of the situation and of what, if any, actions health care professionals and patients should take."

Scrutiny over metformin, a generic drug produced globally, follows the global scare over NDMA contamination in Zantac this summer that led to industrywide recalls. In November, the FDA put out what amounted to a confidence-booster for the drug, saying that the agency's testing found NDMA amounts comparable to that found in "grilled or smoked meats."

But the ball could already be rolling on metformin after the Singaporean Health Sciences Authority announced Wednesday it had recalled three of 46 versions of the drug sold in the country after finding NDMA above the "internationally acceptable amount."

The authority said the risk to patients taking those products was low because those products had been supplied locally for only a short time. 

RELATED: FDA: Zantac carcinogens no more dangerous than 'grilled or smoked meats'