Diabetes Drug ‘Metformin’ Probed for Cancer Causing Chemical

By Howard M. Riell

Does the diabetes drug metformin contain a cancer-causing chemical? Health officials in Europe and the United States believe it may, and are investigating.

The drug is commonly used by millions the world over. Some metformin supplies in Singapore have been recalled after authorities found they contained small amounts of a chemical called NDMA, according to dailymail.com.

“The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) is now considering whether similar action needs to be taken for UK products such as Glucophage. And the US Food and Drug Administration (FDA), Health Canada and the European Medicines Agency are doing the same investigations on their own turf,” the web site reported. “NDMA is a chemical byproduct from pesticides, chlorine and industrial processes and is classified as ‘probably carcinogenic to humans.”

“Over the past year and a half, several drug products including angiotensin II receptor blockers (ARBs) and ranitidine, commonly known as Zantac, have been found to contain small amounts of nitrosamines such as N-Nitrosodimethylamine (NDMA),” said Janet Woodcock, MD, director of FDA’s Center for Drug Evaluation and Research, in a statement. “During this time, there has been an ongoing investigation into the presence of nitrosamines in other drug products. This effort is focused on ensuring the drugs used by Americans continue to meet strict quality standards.”

The FDA is aware that some metformin diabetes medicines in other countries were reported to have low levels of NDMA, she noted. “Based on the information we have available, the levels of NDMA seen outside the U.S. are within the range that is naturally occurring in some foods and in water. While we are aware that some regulatory agencies outside the U.S. may be recalling some metformin drugs, there are no metformin recalls affecting the U.S. market at this time. The FDA is investigating whether metformin in the U.S. market contains NDMA, and whether it is above the acceptable daily intake limit of 96 nanograms.

The agency will also work with companies to test samples of metformin sold in the U.S. and will recommend recalls as appropriate if high levels of NDMA are found. If as part of our investigation, metformin drugs are recalled, the FDA will provide timely updates to patients and health care professionals.”

NDMA is a common contaminant found in water and foods including cured and grilled meats, dairy products and vegetables. Everyone is exposed to some level of NDMA. The FDA and the international scientific community do not expect it to cause harm when ingested at low levels. The acceptable daily intake limit for NDMA in the U.S. is 96 nanograms. Genotoxic substances such as NDMA may increase the risk of cancer if people are exposed to them above acceptable levels and over long periods of time, but a person taking a drug that contains NDMA at-or-below the acceptable daily intake limit every day for 70 years is not expected to have an increased risk of cancer.