FDA: Testing Reveals Unacceptable Levels of NDMA in Two H2 Blockers

The Food and Drug Administration (FDA) has released a summary of the results from tests evaluating ranitidine products for the probable carcinogen N-Nitrosodimethylamine (NDMA).

Based on the tested ranitidine products to date, the NDMA levels found were determined to be low, and “similar to the levels you would expect to be exposed to if you ate common foods like grilled or smoked meats.” The Agency also developed a simulated gastric fluid model to test for the formation of NDMA in stomach and intestinal fluids. The tests showed that NDMA was not formed when ranitidine was exposed to stomach acid or the environment within the small intestine, however human testing is still necessary to confirm these results. 

Although NDMA levels were found to be low in these products, some still exceeded acceptable levels; consuming up to 0.096 micrograms or 0.32 parts per million (ppm) of NDMA per day is considered reasonably safe for human ingestion based on lifetime exposure. As such, the FDA continues to ask manufacturers to recall products that contain NDMA above acceptable limits; both ranitidine and nizatidine, which is chemically related to ranitidine, have been identified in the investigation as having unacceptable levels of NDMA.

For patients taking ranitidine or nizatidine, the FDA continues to recommend that alternative therapies be considered. Testing of ranitidine syrup showed some samples contained NDMA above acceptable levels. Based on the FDA’s tests, the following products do not contain NDMA impurities : Pepcid (famotidine), Tagamet (cimetidine), Nexium (esomeprazole), Prevacid (lansoprazole) and Prisolec (omeprazole).

In a press statement, Janet Woodcock, MD, director of FDA’s Center for Drug Evaluation and Research said, “We know impurities in medicines are of great concern to patients and consumers who rely on safe and effective medicines approved by the FDA, and we are working with manufacturers and global regulators to provide clear and actionable information. These investigations take time and do not provide instantaneous answers.”

For more information visit fda.gov.