A couple of months ago, we wrote about the U.S. Food and Drug Administration (FDA)’s confirmation that it was testing batches of the type 2 diabetes drug metformin for a potential contaminant. This contaminant, N-nitrosodimethylamine — more commonly known as NDMA — may contribute to cancer, and the FDA has established an upper limit for how much of it any drug sold in the United States can contain. NDMA is a potential byproduct of certain drug manufacturing processes.
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Now, the FDA has announced in a press release that the results are in — and there’s very little for anyone who takes metformin to worry about. Out of all the different batches of metformin from different manufacturers that the FDA tested, levels of NDMA range from undetectable to low, coming in well below the agency’s established limit.
In a more detailed announcement of its laboratory analysis, the FDA notes that consuming up to 0.096 micrograms of NDMA is considered “reasonably safe,” based on previous studies examining lifetime exposure to this chemical. According to the FDA, “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.”
Out of nine different metformin formulations from seven manufacturers that the FDA tested, the agency found NDMA in only two — both by the drugmaker Actavis. But these pills contained NDMA at such low levels that they essentially pose no danger, according to the FDA, so no action needs to be taken. In both the 500-milligram and 1,000-milligram extended-release versions of metormin by Actavis, the FDA found either 0.01 to 0.02 micrograms of NDMA, a fraction of the established 0.096-microgram limit.
For perspective, the FDA notes that levels of NDMA found in the two metformin products are “similar to the levels you would expect to be exposed to if you ate foods like grilled or smoked meats.” If you have any questions about the safety of metformin in the wake of these results, talk to your doctor.
Want to learn more about metformin? Read “What to Know About Metformin,” “Diabetes Medicine: Metformin,” and “Metformin: The Unauthorized Biography.”