The Food and Drug Administration is asking the makers of the heartburn medication ranitidine, known widely as the Zantac brand, to pull both prescription and over-the-counter versions of the drug from the market.
The agency said in a Wednesday statement that the drug contains a contaminant that, if stored at above room temperature, presents an "unacceptable" level of consumer exposure to a carcinogen called NDMA.
"We make every effort to investigate potential health risks and provide our recommendations to the public based on the best available science," said Janet Woodcock director of the FDA’s Center for Drug Evaluation and Research.
"We didn’t observe unacceptable levels of NDMA in many of the samples that we tested. However, since we don’t know how or for how long the product might have been stored, we decided that it should not be available to consumers and patients unless its quality can be assured."
The agency had warned previously that Zantac contained the carcinogen, but didn't ask Sanofi to withdraw the drug from the market. In October, Sanofi voluntarily recalled Zantac OTC in the U.S. and Canada. Novartis pulled its versions of ranitidine in September.
The FDA also urged consumers to stop taking the drug.
Paris-based Sanofi is also undertaking a clinical trial of a drug to treat patients hospitalized with severe Covid-19.