What Is Zantac Cancer?

Blister pack of medication

WIN-Initiative / Stone / Getty Images

Zantac (ranitidine), an over-the-counter heartburn medication, was pulled from drugstore shelves in April 2020 when some samples of the drugs were found to contain unacceptable levels of a potential carcinogen (cancer-causing substance) called N-nitrosodimethylamine (NDMA).

The Food and Drug Administration (FDA) issued a mandatory withdrawal order that applied to both Zantac and generic ranitidine formulations and is in place as of reporting, pending further investigation.

Alarms were first raised by a small online pharmacy called Valisure, which in June 2019 alerted the FDA to high levels of NDMA in a generic ranitidine formulation.

After this, several manufacturers began to voluntarily withdraw the drug, starting with Novartis in September 2019 followed soon after by Sanofi, GlaxoSmithKline, and other producers of the top-selling medication. 

When higher-than-acceptable levels of NDMA were found in some tested samples, the FDA issued a mandatory withdrawal order. Officials stated that they “determined that the impurity in some ranitidine products increases over time and when stored at higher than room temperatures and may result in consumer exposure to unacceptable levels of this impurity.”

In the wake of this finding, over 40 countries, including the European Union and Australia, have removed Zantac from store shelves until further safety evaluations can be completed.

Learn everything you need to know about the potential Zantac-cancer link and what to do if you have a history of taking this medication.

What is Zantac? 

Zantac (ranitidine) is a medication in a class of drugs known as histamine-2 (H2) blockers which decrease the production of acid in the stomach. In 2020, Zantac and generic ranitidine formulations sold more than 16 million units in the United States, making it the 48th most popular drug in the United States.

Previously, Zantac was used over-the-counter to prevent and treat symptoms of heartburn associated with indigestion and acid reflux. It was also prescribed to treat ulcers, gastroesophageal reflux disease (GERD), and health conditions where the stomach produces too much acid such as Zollinger-Ellison syndrome.

In addition to the familiar OTC tablet and capsules, ranitidine was also available as a pediatric syrup and sometimes used to treat ulcers in children as young as one year of age.

What Is NDMA? 

NDMA is an environmental contaminant that belongs to a class of potential carcinogens called N-nitrosamines. Small amounts of NDMA can be found in the soil, air, and water as well as in certain foods including cured meats like bacon, sausage, fish, and cheese as well as beer and whiskey.  

NDMA and other N-nitrosamines are produced by chemical reactions to nitrites and nitrates found in many smoked, cured, or processed foods, tobacco smoke, and chewing tobacco. NDMA can be found in some workplaces as a byproduct of manufacturing processes at tanneries, rubber and tire manufacturers, and pesticide manufacturing plants.

It’s also produced as a result of the chlorination of drinking and wastewater as a part of the purification process, and can be found in some municipal chlorinated water supplies. The Environmental Protection Agency does not currently have a federal standard for NDMA in drinking water, but it is listed as a priority pollutant.

In medications, the FDA considers NDMA levels of less than 96 ng/day (or 0.32 parts per million) safe for daily consumption.

How Cancerous Is NDMA? 

NDMA is classified as a “probable human carcinogen," per the FDA. This is based on research that shows animals such as rats and mice exposed to high levels of NDMA develop liver damage and cancer.

As of yet, it is unclear exactly how carcinogenic NDMA may be in humans. While exposure to NDMA does not guarantee negative health effects will follow, it is reasonable to expect that it could cause cancer in humans, according to the U.S. Department of Health and Human Services. 

What scientists do know about NDMA’s potential health impacts on humans is that it can cause hepatoxicity (liver poisoning). Animal studies have shown that NDMA, when metabolized by the liver, can stimulate the release of inflammatory cytokines that cause liver inflammation, leading to fibrosis and cirrhosis (scarring of the liver).

However, the amount used in these studies far exceeded what humans are routinely exposed to, per a 2015 article published in Interdisciplinary Toxicology. Even so, the cumulative exposure to NDMA over a lifetime may pose a potential risk to humans over time.

The link between NDMA and cancer in humans is less clear. A few studies have shown that NDMA causes liver damage in non-human primates but not liver cancer.

To date, there are few studies that demonstrate a direct correlation between NDMA and cancers in humans. However, the high intake of foods that contain nitrates and nitrates—both of which are associated with stomach, kidney, and colon cancer—means we cannot discount the role NDMA may play in cancer development.

Should I Be Concerned? 

It's important to take warnings about Zantac, NDMA, and cancer seriously while at the same time understanding there are limits to what we know so far. Multiple class action cases have been filed claiming that ranitidine either causes or contributes to the onset of cancer. However, there is as of yet no definitive evidence that Zantac directly causes cancer.

This doesn’t mean there’s nothing to worry about. One of the more frequently-cited studies circulated by law firms shows that a 150-milligram (mg) dose of ranitidine increases the urinary excretion of NDMA by over 400-fold—a rise from 110 nanograms (ng) to 47,600 ng.

These levels are alarming, but they still don’t mean that you will get cancer due to this level of exposure. Right now, scientists simply don’t know. For a definitive answer on whether Zantac can cause cancer, more research is needed. 

A Word From Verywell 

If you take Zantac or have in the past, it’s normal to feel concerned about rumors of a link to cancer and wonder what you should do. Until the scientific community better understands what risk Zantac poses, it is best to use other medications to treat occasional heartburn and other gastrointestinal conditions.

That said, don't just flush your medication down the toilet. Ask your healthcare provider about how you can safely stop using it, dispose of it, and find alternative medications.

Keep in mind that the FDA order does not extend to some other over-the-counter drugs also used to reduce heartburn and stomach acid such as Pepcid (famotidine), Tagamet (cimetidine), Nexium (Nexium esomeprazole), or Prevacid (lansoprazole).

Always speak with your healthcare provider before using any OTC H2 blocker or proton pump inhibitor such as Prilosec (omeprazole), especially if you’re living with a chronic condition. 

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. U.S. Food and Drug Administration. FDA requests removal of all ranitidine products (Zantac) from the market.

  2. American Society of Health-System Pharmacists, Inc. Ranitidine.

  3. Park JE, Seo JE, Lee JY, Kwon H. Distribution of seven N-nitrosamines in food. Toxicol Res. 2015 Sep;31(3):279-88. doi:10.5487/TR.2015.31.3.279. Erratum in: Toxicol Res. 34(4):371.

  4. Environmental Protection Agency. Technical fact sheet – N-nitroso-dimethylamine (NDMA).

  5. U.S. Food and Drug Administration. Laboratory tests | Ranitidine.

  6. U.S. Food and Drug Administration. Statement alerting patients and health care professionals of NDMA found in samples of ranitidine.

  7. Agency for Toxic Substances and Disease Registry. Public health statement for n-nitrosodimethylamine.

  8. Mukherjee D, Ahmad R. Dose-dependent effect of N'-Nitrosodiethylamine on hepatic architecture, RBC rheology and polypeptide repertoire in Wistar ratsInterdiscip Toxicol. 8(1):1-7. doi:10.1515/intox-2015-0001

  9. Adamson RH, Chabner BA. The finding of N-nitrosodimethylamine in common medicinesOncologist. 25(6):460-462. doi:10.1634/theoncologist.2020-0142

  10. cite

    Zeng T, Mitch WA. Oral intake of ranitidine increases urinary excretion of N-nitrosodimethylamine. Carcinogenesis. 37(6):625-634. doi:10.1093/carcin/bgw034

By Lauren Krouse
Lauren Krouse is a journalist especially interested in covering women’s health, mental health, and social determinants of health. Her work appears in Women's Health, Prevention, and Self, among other publications.