Australia’s Therapeutic Goods Administration (TGA) is preparing to update a recent Zantac warning, after a cancer-causing chemical turned up in three-quarters of the ranitidine tablets it’s tested so far.
The Australian developments come just over a month after the U.S. Food & Drug Administration (FDA) first notified the public that some Zantac and ranitidine tablets had tested positive for the presence of N-nitrosodimethylamine (NDMA), a probable human carcinogen.
The FDA was informed of the contamination by Valisure, an online pharmacy that tests each batch of medications it sells. The company apparently detected the chemical in every sample of ranitidine tested, often at levels that far exceeded the maximum daily limits established by the FDA.
While the FDA has conceded that some Zantac tests found “unacceptable” levels of NDMA, the agency attributed those findings to Valisure’s high-temperature testing method. However, a low-temperature method favored by the FDA has also found NDMA in ranitidine, although in lower amounts.
Valisure continues to urge the FDA to order a recall for all Zantac and ranitidine products, noting that a separate analysis involving conditions similar to the human stomach generated over 300,000 nanograms of NDMA, significantly higher than the FDA’s daily limits. The company suggested the presence of the chemical resulted from the instability of the ranitidine molecule, which degrades under conditions similar to those created by digestion.
Nevertheless, the FDA is only advising consumers who take over-the-counter Zantac or ranitidine to consider switching to another heartburn drug. Those using prescription versions should not stop treatment without speaking to a doctor, as doing so could cause their condition to worsen.
While the FDA has not ordered a Zantac recall, several companies, including GlaxoSmithKline, Novartis’s Sandoz subsidiary, Dr. Reddy’s Laboratories, and Apotex, have either recalled their ranitidine products or suspended sales of the drugs. Various retailers, including Walgreens, Wal-Mart, CVS, and Rite-Aid, have also pulled the medications from store shelves.
Australia’s TGA recalled Zantac and ranitidine products on October 4th.
Since then, the regulator has detected NDMA at three parts per million in about 75% of the 138 medication batches it’s tested.
“We’ve found a range of manufacturers in different countries — five altogether — and that’s spread across a number of suppliers,” Professor Paul Kelly, the TGA’s chief medical advisor, said during an interview with 7:30, a nightly Australian news broadcast.
“So yes, it could be a generic issue with the actual manufacture or it could be something to do with the drug itself.”
While the TGA is preparing add the latest findings to its earlier Zantac warning, Kelly maintained that the risk of cancer remains low.
“If someone were to take a ranitidine tablet for their entire life for 70 years, every day, then the risk of cancer may go up by about one in 100,000, so I think you can see from those figures it’s a very small risk,” he said.