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Zantac Recall: Does Ranitidine Cause Cancer?

Late September 2019, Valisure filed a Citizen Petition urging the FDA to recall ranitidine.

Although several drug companies and major drug store chains quickly suspended sales of Zantac and its generic ranitidine voluntarily, the FDA did not issue a total recall, in contrast to many health authorities overseas.

But what prompted Valisure to request ranitidine be pulled from our shelves?

Ranitidine and NDMA

The reason a recall was sought was that traces of N-nitrosodimethylamine (NDMA) were found in ranitidine generics.

NDMA is a type of nitrosamine compound and classified as a probable carcinogen in humans by the International Agency for Research on Cancer (IARC). NDMA is commonly found in smoked and cured meats, tobacco smoke, toiletries and cosmetics and sometimes in drinking water, particularly that which has undergone chlorination. Consumption of NDMA has been positively associated with gastric and colorectal cancer.

Initial testing suggested generic Zantac was “contaminated” with NDMA; however, it now appears that ranitidine is a fundamentally unstable molecule and NDMA forms during the degradation or breakdown of the molecule, meaning that no form is safe. 

How was NDMA Discovered in Zantac and its Generics?

NDMA was discovered in Zantac and its generics by Valisure, which performs independent chemical analyses on a wide range of generic drugs and some brands.

Valisure launched in the U.S. in 2018, becoming the first company to ensure imported generics and some brands meet all the Good Manufacturing Practice (CGMP) regulations set by the FDA. These regulations are supposed to ensure that any ingredient or raw materials used in the manufacture of medicines are free from contaminants or impurities. The FDA itself only has resources to spot check a few dozen batches every year and relies on self-reporting of compliance by the original manufacturer. 

Valisure started to test for NDMA soon after the FDA found traces of the carcinogen in the blood pressure drug, Valsartan. Ranitidine was one of the first compounds Valisure tested because the company’s cofounder had an infant daughter taking the drug. Using a high-heat test, which involves heating the product to 266°F (130 °C), an alarming 3mg of NDMA was found in a single 150mg ranitidine tablet.

While the FDA challenged Valisure’s original testing method, subsequent retesting at lower temperatures still revealed levels of NDMA classified as unacceptable by the FDA. Further tests revealed NDMA as a breakdown product of ranitidine on exposure to chlorine and ozone, and even more worryingly, in a test that mimicked stomach acid. The stomach acid test yielded 300,000 ng (nanograms) of NDMA from one tablet, a level 3000 times higher than the FDA’s allowable daily limit of 92 ng.

Does Zantac Pose a Cancer Risk?

Although consumption of NDMA has been positively associated with gastric and colorectal cancer, experts aren’t exactly sure just how big a risk it poses. As for NDMA being found in ranitidine, it is important to know that there are no immediate health risks associated with its use nor currently any reports of adverse events related to its presence in ranitidine.

Ranitidine belongs to a class of medicines called H2 antagonists and these have always only been recommended for short term use. So, if you are still taking a form of ranitidine, now is a good time to talk to your doctor about stopping it or switching to another similar type of drug. Valisure found NDMA in only one other H2 antagonist, nizatidine, but levels were 70 times lower than those in ranitidine. Other H2 antagonists (such as famotidine or cimetidine) and proton pump inhibitors (PPIs), such as omeprazole or esomeprazole, tested free from NDMA.

Posted: November 2019

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