The FDA requested that manufacturers immediately pull all prescription and over-the-counter (OTC) ranitidine drugs from the market, saying new evidence indicates users could be exposed to “unacceptable levels” of the probable carcinogen N-nitrosodimethylamine (NDMA) over time under certain conditions. Last year, the FDA, along with other regulators around the world, began looking into possible NDMA contamination of drugs containing the H2 blocker, after the impurity was detected in both branded and generic versions of Sanofi’s OTC heartburn medicine Zantac.
The FDA noted that while low levels of NDMA would not be expected to lead to an increased risk of cancer, sustained higher levels of exposure may do so. In its latest advisory, the agency said new data suggest NDMA levels increase in ranitidine “even under normal storage conditions,” while the contaminant has been found to rise “significantly” in samples stored at higher temperatures, including those the product may be exposed to during distribution and handling by consumers.
New evidence also indicates that “the older a ranitidine product is, or the longer the length of time since it was manufactured, the greater the level of NDMA,” the FDA said, adding “these conditions may raise the level of NDMA in the ranitidine product above the acceptable daily intake limit.” The agency is also advising consumers to stop taking any OTC ranitidine products they may have on hand and consider using other approved OTC products, noting that to date, testing has not found NDMA in famotidine, cimetidine, esomeprazole, lansoprazole or omeprazole.
Last October, Sanofi voluntarily recalled Zantac in the US and Canada as a precautionary measure due to possible contamination with NDMA. The move followed similar actions taken by drugmakers such as GlaxoSmithKline and Novartis’ Sandoz unit, as well as US pharmacy chains CVS Health and Walgreens.
Aside from ranitidine, small quantities of NDMA have also been detected in angiotensin II receptor blockers, although the FDA has since said “the actual risk to patients is likely much lower than our estimates.” In addition, global regulators are investigating levels of the contaminant in the type 2 diabetes drug metformin.