Nitrosamines: US health agency investigates cancer risks in metformin, ranitidine, others


Adeze Ojukwu


The United States(US) Food and Drug Administration(FDA) has once again, raised serious concerns about potential cancer risks associated with consuming medications, that contain high levels of nitrosamines.

In a report, tagged “What to Know and Do About Possible Nitrosamines in Your Medication,” FDA said it was “investigating several potentially cancer-causing substances, called nitrosamines, recently found in some drugs, including those used to treat elevated blood pressure, heartburn, acid reflux, and diabetes.”

“Some of these drugs from certain manufacturers – including angiotensin II receptor blockers (ARBs), ranitidine, nizatidine, and metformin – have been recalled because of nitrosamine impurities.”

The US apex health agency has requested manufacturers to withdraw all ranitidine, brand name Zantac, products in the U.S. market. The FDA knows this is a concern.

This action is highly commendable and other nations, should take similar measures, in order to avert the risks posed to users.

This is indeed a global public health concern, because metformin, an antidiabetic and ranitidine recommended for gastrointestinal issues, are popular medications in Nigeria, India and other parts of the world.

This development requires urgent response from various health regulatory bodies in Nigeria and other places.

Most recently, the FDA “announced that its testing showed levels of the nitrosamine N-Nitrosodimethylamine (NDMA) in some samples of the extended release (ER) formulation of the diabetes medicine metformin that exceed the agency’s acceptable intake limit.”

The FDA requested that five manufacturers of those medicines voluntarily recall metformin ER with NDMA above the acceptable intake limit.

The agency also asked “all manufacturers of ER versions of metformin to evaluate their risk of excessive NDMA and to test at-risk products before each batch is released onto the U.S. market. If testing shows NDMA above the acceptable intake limit, the manufacturer should inform the agency and should not release the batch to the U.S. market.”

The agency “continues to work with manufacturers to investigate the source of nitrosamines in drug products and whether they are at a level that may pose risks to human health. The FDA and manufacturers are testing samples of certain medications that may contain nitrosamines and will continue to take quick and appropriate action when needed to protect American consumers.”

Excerpts of the report are below:
“Nitrosamines are organic compounds that we are exposed to in our everyday lives. They exist in low levels in our water and foods, including meat, vegetables, and dairy products.”

“Nitrosamines come from chemical reactions and can form in drugs during manufacturing. These chemicals are scientifically called N-Nitrosodimethylamine (NDMA), N-Nitrosodiethylamine (NDEA), and N-Nitroso-N-methyl-4-aminobutyric acid (NMBA).”

“Some nitrosamines may increase the risk of cancer if people are exposed to them above acceptable levels and over long periods of time. People taking drugs that contain NDMA at or below the acceptable intake limits every day for 70 years are not expected to have an increased risk of cancer.”

“Don’t abruptly stop taking your prescription medications without first talking to your health care provider. Your health care professional has a more complete picture of your health and health history and can help you make the best decisions for your care.”

“They know about your health condition, including understanding what other drugs have worked for you or not, and can help determine the next steps if your drug has been recalled.”

“Consumers taking nonprescription nizatidine can consider using other over-the-counter (OTC) products to treat their condition.”

“The FDA has requested that manufacturers withdraw all remaining prescription and OTC ranitidine on the U.S. market, known commonly by the brand name Zantac. This means ranitidine will not be available for new or existing prescriptions or OTC use in the U.S. Consumers should stop taking any OTC ranitidine they may currently have.”

“ Patients currently taking prescription ranitidine should contact their health care professional to discuss alternatives before they stop taking the medicine. Multiple drugs are approved for the same or similar uses as ranitidine. Consumers should dispose of any ranitidine products properly, and not buy more of it.”