Since its approval for marketing in the United States in 1994, metformin has become the first-line drug for treating type 2 diabetes. It’s no exaggeration to say that this medicine has revolutionized how type 2 is treated, since it lowers blood glucose levels without the significant risk of hypoglycemia (low blood glucose) associated with older classes of drugs for type 2. It also appears to have a range of secondary benefits, from weight loss to better heart health to improved cognition to reduced anxiety.
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But in the wake of warnings from the Food and Drug Administration (FDA) that low levels of the potentially cancer-causing contaminant N-nitrosodimethylamine (NDMA) were found in the acid reflux drug Zantac (ranitidine), the agency has confirmed that it is testing samples of metformin for the same substance, according to a report from Bloomberg. The agency indicated that it was looking at metformin made by various manufacturers, and that it would take appropriate action — including recalls if necessary — if unacceptably high levels of NDMA are found.
“The agency is in the beginning stages of testing metformin,” reads an emailed statement from FDA spokesman Jeremy Kahn, per the Bloomberg report. “However, the agency has not confirmed if NDMA in metformin is above the acceptable daily intake (ADI) limit of 96 nanograms in the U.S.”
The statement emphasizes that no one should stop taking metformin without first talking to their doctor. If any contamination is eventually detected, it will most likely be possible to safely switch to another brand of metformin if your brand is recalled.
NDMA can be accidentally created through various industrial processes, including those used in drug-making. The risk of its presence in metformin isn’t just hypothetical, since Singapore just announced the recall of three different formulations of metformin, out of 46 that are sold in the country. None of these three versions of metformin is sold in the United States.
A freelance health writer and editor based in Wisconsin, Phillips has a degree in government from Harvard University. He writes on a variety of topics, but is especially interested in the intersection of health and public policy.