Based on results from laboratory testing, the U.S. Food and Drug Administration has learned that Zantac® and other ranitidine medicines 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 in humans. NDMA is a known environmental contaminant and found in water and foods, including meats, dairy products, and vegetables.
N–nitrosodimethylamine (NDMA) is classified as a probable human carcinogen which means that it is more likely than not to cause cancer in humans. NDMA has been studied in animal populations and found to increase the occurrence of cancer in the animals. The studies have raised the specter of an association between NDMA and liver toxicity which can lead to the development of liver cancer and other related conditions brought about by an NDMA–induced “insult” to the liver.
The degree and duration of human NDMA exposure that can lead to the development of cancer is not precisely known. Similarly, the extent and duration of the NDMA contamination of Zantac® and other ranitidine medicines are not precisely known. Efforts are underway to define the scope and degree of the NDMA contamination.
NDMA has been studied in animal populations and found to increase the occurrence of cancer in the animals. In light of these studies, the U.S. Environmental Protection Agency classifies NDMA as a probable human carcinogen. The studies have raised the specter of an association between NDMA and liver toxicity which can lead to the development of liver cancer and other related conditions brought about by an NDMA–induced “insult” to the liver. Some have suggested that NDMA may also be linked to other cancers such as:
As of April 1, 2020, the FDA requested that all manufacturers withdraw all prescription and over-the-counter (OTC) ranitidine drugs from the market. The FDA determined that impurity levels of NDMA could actually increase over time when the drug was stored at higher than room temperature. In their April 1 press release, the FDA advised the following:
The FDA is committed to ensuring that the medicines Americans take are safe and effective. We make every effort to investigate potential health risks and provide our recommendations to the public based on the best available science. We didn’t observe unacceptable levels of NDMA in many of the samples that we tested. However, since we don’t know how or for how long the product might have been stored, we decided that it should not be available to consumers and patients unless its quality can be assured,” said Janet Woodcock, M.D., director of the FDA’s Center for Drug Evaluation and Research. “The FDA will continue our efforts to ensure impurities in other drugs do not exceed acceptable limits so that patients can continue taking medicines without concern.”