NDMA in Zantac

Zantac and its generic active ingredient, ranitidine hcl, metabolizes into N-nitrosodimethylamine (NDMA) a chemical that the FDA, the U.S. Environmental Protection Agency (EPA), and the World Health Organization (WHO) all classify as a (cancer-causing) carcinogen.

The FDA established a 96 ng (nanograms) per day intake limit of NDMA (though even this intake limit may be too high). However, recent testing of Zantac using FDA-approved methods found more than 2,500,000 ng of NDMA in a Zantac 150 mg tablet, the dosage countless people take every day.

IMPORTANT ZANTAC FDA UPDATE: On April 1, 2020, the FDA announced that it is requesting drug makers to immediately withdraw Zantac and generic ranitidine (Zantac OTC) drugs from the market. In its ongoing investigation, the FDA determined that N-Nitrosodimethylamine (NDMA) in some Zantac drugs “increases over time and when stored at higher than room temperatures and may result in consumer exposure to unacceptable levels…”

What is NDMA?

N-Nitrosodimethylamine (NDMA) is a water-soluble organic (containing the element carbon) chemical that was discovered long ago in the process of developing rocket fuel. Its chemical formula is C₂H₆N₂O. NDMA essentially consists of a nitrite group (NO₂) attached chemically to a dimethylamine (DMA) group ((CH₃)₂NH). This fact is fundamental to the Zantac cancer connection that is discussed below.

NDMA is a yellow liquid with little or no obvious taste or odor. It can be produced as a byproduct of manufacturing processes and humans can be exposed to NDMA in relatively small amounts through a variety of products, including tobacco, foods (cured meat, fish, cheese, beer), shampoos, cleansers, and pesticides.

NDMA Cancer Mechanism

Cancer is known to be the result of chronic exposure to carcinogens, leading to repeated DNA damage, which the body is unable to fully repair, and finally, to genetic mutations. The NDMA cancer mechanism has been studied extensively. When NDMA enters the body, the body’s own defense system is activated. The “army” sent to destroy foreign invaders consists, in part, of a family of enzymes (proteins) known as cytochrome P450. These enzymes engage the foreign substances in complex chemical reactions.

One of the CYP450 “soldiers”—the one that is thought to target NDMA—is an enzyme known as CYP2E1. As a result of the NDMA-CYP2E1 interaction and subsequent chemical reactions, the organic compound methyldiazonium ion (MI) is formed. MI is referred to in scientific literature as an “ultimate carcinogen,” meaning that it interacts directly with cellular DNA to initiate carcinogenesis. MI does this through a process known as DNA methylation, the addition of a methyl group to the DNA molecule. DNA methylation is a normal process that affects the expression of genes—that is, the activation or suppression of the genetic instructions to make a particular product, generally a protein. Abnormal methylation caused by NDMA, however, can lead to cancer.

Scientists are also gaining detailed knowledge of the biochemical mechanisms used by the body to repair NDMA DNA damage and how those mechanisms play a role in the progression towards cancer.

Zantac NDMA Cancer Risk

Over the last 40 years, several studies have made the case that NDMA is a carcinogen. According to the World Health Organization (WHO), “NDMA is clearly carcinogenic. There is overwhelming evidence that NDMA is mutagenic and clastogenic.”

NDMA belongs to a family of chemicals known as N-nitrosamines. According to the EPA, N-nitrosamines are “a family of potent carcinogens.”

Glaxo Laboratories (now GlaxoSmithKline, or simply GSK) developed Zantac (ranitidine hydrochloride), and it was first used commercially in 1981. In the years since, Pfizer, Johnson & Johnson, Boehringer, and Sanofi have controlled the over-the-counter Zantac rights.

The interesting thing about NDMA and Zantac is that, contrary to the FDA’s assertion that NDMA is an impurity, NDMA is not added to Zantac; it is a byproduct of the chemical processes that happen when a person ingests ranitidine.

When Zantac interacts with stomach acid and heat in that environment, the molecule transforms into NDMA. That is why people who take Zantac are shown to have more than 400 times the legal allowable limit of NDMA in the urine. Put simply, NDMA is created during the process of digesting Zantac, which is why the Zantac cancer risk had not been discovered until recently.

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