- The Food and Drug Administration said its early, limited testing has shown "unacceptable levels" of a carcinogen in samples of ranitidine, a generic heartburn medicine commonly known by its brand name Zantac.
- That's a change from a patient alert in September, when the agency said levels of carcinogen N-Nitrosodimethylamine, or NDMA, found in preliminary tests "barely exceed amounts you might expect to find in common foods."
- Still, the FDA in an Oct. 2 statement challenged claims from a third-party laboratory that suggest the NDMA contamination is even more dangerous. The online pharmacy Valisure, whose lab originally identified the problem and informed the FDA, said it's found NDMA in excess of 300,000 ng per ranitidine tablet, well more than the permissible limit of 96 ng.
Concern over the possible cancer-causing contamination is mounting around the world. Earlier this week, major pharmacy chains including CVS announced they would stop selling Zantac. That followed a recall by Novartis' Sandoz unit for prescription ranitidine capsules.
Valisure has been pressuring the FDA to request a recall of all ranitidine products, saying the molecule itself has an inherent instability. In a Sept. 9 citizen petition, Valisure said its lab has found NDMA in every lot tested, covering a variety of manufacturers and dosages.
The FDA said it's asking manufacturers to conduct their own tests of ranitidine and to send samples to be analyzed by agency scientists. The FDA criticized the third-party lab for using higher temperatures, saying "that method is not suitable for testing ranitidine because heating the sample generates NDMA."
While the agency didn't single out Valisure by name, the lab has presented a different narrative than the FDA. In an e-mailed statement, Valisure said it developed a body-temperature testing method to analyze ranitidine that doesn't by itself generate NDMA.
"Ranitidine is so unstable that a wide variety of conditions have been shown to degrade it into NDMA by many scientific groups," Valisure said.
The pharmacy also urged consumers to return any lots of ranitidine to a pharmacy for proper disposal, to avoid the risk of contaminating drinking water by throwing pills into the sink, toilet or trash.