The Food and Drug Administration announced that it has asked companies to voluntarily recall a diabetes drug because it could contain a probable carcinogen. The drug, an extended-release formulation of metformin, was found in several lots to contain N-Nitrosodimethylamine (NDMA).
“The agency is in contact with five firms to recommend they voluntarily recall their products,” the FDA wrote in a press release. The agency found “levels of the nitrosamine impurity N-Nitrosodimethylamine (NDMA) above the agency’s acceptable intake limit in several lots of the extended-release (ER) formulation of metformin, a prescription drug used to control high blood sugar in patients with type 2 diabetes.”
The FDA says that “company recall notices will be posted on FDA’s website.” But despite the discovery of the probable carcinogen, the FDA has recommended that patients should continue taking the metformin until their health professional can find a replacement.
According to the FDA:
Nitrosamine impurities may increase the risk of cancer if people are exposed to them at above-acceptable levels over long periods of time, but we do not anticipate that shorter-term exposure at levels above the acceptable intake limit would lead to an increase in the risk of cancer.
In a previous statement, the FDA explained, “NDMA is classified as a probable human carcinogen (a substance that could cause cancer) based on results from laboratory tests. NDMA is a known environmental contaminant and found in water and foods, including meats, dairy products, and vegetables.”
What Does Metformin Do?
Type-2 diabetes affects how the body metabolizes glucose and reduces the body’s ability to produce enough insulin to maintain proper glucose levels. Metformin is an oral medicine for diabetes to help control blood sugar and can be used along with insulin or other medications, according to Drugs.com.
The investigation began when the heartburn drug Zantac was recalled due to NDMA contamination, according to Reuters. This prompted the FDA to start an investigation into metformin company producers in December. The agency had found low levels of NDMA in some metformin samples in February of 2020, but it did not test at levels considered too high.
The FDA announcement only named the company Apotex, which voluntarily recalled its extended-release metformin drug “out of an abundance of caution,” according to the New York Post. However, the FDA didn’t name the other four drugmakers.
The FDA has said, however, that immediate-release metformin medications do not seem to have any issues. According to Reuters, an independent company called Valisure said that its tests showed 11 metformin-producing companies’ drugs contained high levels of NDMA.
The FDA has also found carcinogenic nitrosamines in medications for elevated blood pressure, heartburn and acid reflex along with the Zantac medication.
What is NDMA?
Nitrosamines are molecules that contain the nitroso functional group of human carcinogens. NDMA is classified by the World Health Organization‘s International Agency for Research on Cancer as “probable human carcinogens.”
NDMA affects many organs and especially the liver. According to research from the Environmental Protection Agency,
..one was a chemist who was exposed to unknown concentrations of fumes and experienced “exhaustion, headache, cramps in the abdomen, soreness on the left side, nausea and vomiting for at least two years” (Freund, 1937). The second case was an automobile factory worker who was exposed to unknown levels of NDMA and became violently ill with jaundice and ascites (Hamilton and Hardy 1974).
Exposure was also found to have respiratory, cardiovascular and gastrointestinal effects.
The FDA explained that there are many reasons for why NDMA can be found in drugs at high levels, including if the drug manufacturing process, chemical structure, storage and packaging conditions. According to the FDA, “As food and drugs are processed in the body, nitrosamines, including NDMA, can be formed.”
The FDA has said it will post recall notices on its website.