The Zantac problem: What’s NDMA?

Zantac has not been recalled but it's not in stores.

September 23, 2019, 4:09 PM

Several countries around the world are taking steps to restrict sales of Zantac and generics that are made of ranitidine, a popular acid reducer, because the FDA and European regulators learned about a link between this medication and the potentially dangerous chemical, NDMA (scientific name N-Nitroso-dimethylamine).

The US FDA announced they had discovered, “that some ranitidine medicines, including some products commonly known as the brand-name drug Zantac, contain a nitrosamine impurity called N-nitrosodimethylamine (NDMA) at low levels. NDMA is classified as a probable human carcinogen (a substance that could cause cancer) based on results from laboratory tests.”

The regulating agencies discovery was released the same day that online pharmacy and laboratory company, Valisure, submitted a petition requesting a recall and safe destruction of all products containing ranitidine.

In their petition which was shown to ABC News, Valisure, which promises customers they will test each lot of medication before distributing it, proposed the idea that the NDMA was the result of the formulation of the ranitidine molecule, which they think may break down when it is digested in the human body creating NDMA.

Ranitidine is a very common over-the-counter and prescription stomach acid blocker that is widely given to babies, adults, and the elderly. Because of its widespread use David Light, the CEO of Valisure says, “There’s no acceptable cancer risk for a drug like this.”

In the United States Zantac maker Sanofi has not halted sales, “The FDA reported that the levels of N-nitrosodimethylamine (NDMA) in ranitidine in preliminary tests barely exceed amounts found in common foods," said the company in a statement.

But Sandoz a division of Novartis, which distributed the generic form of the medication at first halted sending the medication out to stores, and now has instituted a recall.

What is NDMA?

NDMA is a chemical found in both industrial and natural processes. It is classified as a probable carcinogen --a cancer-causing chemical -- according to the Environmental Protection Agency. NDMA acts as a carcinogen “because it modifies your DNA,” Dr. William Mitch, a professor of civil and environmental engineering and wastewater expert at Stanford University, said in an interview with ABC news.

A customer service specialist at Sandoz stated, “NDMA has been shown to increase cancer risk in animal experiments while NDMA has been shown to increase cancer risk in animal experiments, there is no consistent evidence as to how much this substance may potentially increase cancer risk in humans.”

Does ranitidine, a medication given to babies, contain NDMA?

Packages of Zantac sit on a shelf at a drugstore, Sept. 19, 2019, in New York.
Drew Angerer/Getty Images

“We do not know for sure,” Mitch said. The leading theory is that enzymes in the body react with ranitidine to create NDMA. Studies from Stanford by Mitch and his team, show that people who take ranitidine have high levels of NDMA in their urine, suggesting that it is created in the body.

Why is this news now?

The distribution decision by Sandoz only recently happened, but people are concerned that ranitidine has been on the market for years. “If the levels of NDMA is that high, have we missed or not seen the cancer?” asked Dr. Jon Ernstoff, a gastroenterologist.

Academics have recently focused on potential sources of NDMA, as the levels of NDMA in wastewater are rising. As common blood pressure medications were implicated earlier this year, a handful of pharmacies have been on higher alert to test their medications.

On their website Valisure says, “Valisure discovered the link of Zantac and its generics to the carcinogen NDMA during routine testing and first notified the FDA of its initial findings in June of 2019 before submitting their petition on September, 13th.

The distribution decision by Sandoz only recently happened, but people are concerned that ranitidine has been on the market for years. “If the levels of NDMA is that high, have we missed or not seen the cancer?” asked Dr. Jon Ernstoff, a gastroenterologist and an external consultant for Valisure.

“We are working closely with the FDA and are conducting our own robust investigations to ensure we continue to meet the highest quality safety and quality standards," Sanofi said in a statement.

How do you know if you have been affected?

The health effects of overexposure to NDMA include jaundice, nausea, fever, vomiting, abdominal cramps and dizziness. High levels of exposure can cause reduced function of the kidneys and lungs. Please talk to your doctor if you are on ranitidine and experience these side effects. Medical research needs data. “We need to see cause and effect. That has not been done yet,” Ernstoff said in response to concerns about ranitidine, NDMA and cancer.

Should you stop taking ranitidine?

“I don’t think it’s a panic situation for most people," Ernstoff said. "The public should be aware that there are alternatives. Other medications are equally effective."

At this time, the FDA and European regulatory agencies are not telling people to stop taking Zantac, if prescribed by their doctors. Please talk to your doctor if you have concerns about ranitidine. Sandoz has removed its products while Sanofi has not.

Sanofi said, “there are currently no plans to stop distributing or manufacturing Zantac or other ranitidine products outside of Canada.”

The “precautionary release and distribution stop for all our Sandoz ranitidine-containing medicines in all our markets will remain valid until further clarification. We are in close contact with the health authorities,” the company said in a statement.

Sejal Parekh, M.D. is a pediatrician in San Diego who is currently writing for ABC News' Medical Unit.

Tulsie N. Patel, M.D. is a chief resident in psychiatry from Dallas, Texas, working with the ABC News Medical Unit.