The FDA has recommended recalls of certain metformin products that may contain the impurity N-nitrosodimethylamine (NDMA) above the acceptable intake limit. Its laboratory testing found NDMA in certain lots of extended release (ER) metformin. The FDA pages cited here carry dates from 06/05/2020 to 01/06/2021 and cannot tell a reader about any product on the market today.
What the FDA found and recommended
These statements come from three FDA pages. The dates are the ones shown on each page.
| Question | What the source says |
|---|---|
| What did the FDA recommend? | Recalls of certain metformin products that may contain NDMA above the acceptable intake limit (question-and-answer page, content current as of 09/03/2020). |
| What did FDA testing find in ER metformin? | NDMA in certain lots, with FDA recommending companies recall lots with levels of NDMA above the acceptable intake limit of 96 nanograms per day (laboratory analysis page, content current as of 06/05/2020). |
| What about immediate release (IR) metformin? | FDA testing has not shown NDMA in IR metformin products, described as the most commonly prescribed type of metformin (update page, content current as of 01/06/2021). |
What the FDA says about cancer risk
The question-and-answer page states that nitrosamine impurities may increase the risk of cancer if people are exposed to them at above acceptable levels over long periods of time. It adds that the FDA does not anticipate that shorter term exposure at levels above the acceptable intake limit would lead to an increase in the risk of cancer.
The laboratory analysis page states that 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.
What the FDA says patients and clinicians should do
The FDA update page says patients taking recalled ER metformin should continue taking it until a doctor or pharmacist gives them a replacement or a different treatment option.
It also states that it could be dangerous for patients with type 2 diabetes to stop taking their metformin without first talking to their health care professional. For health care professionals, it states that the FDA recommends continuing to prescribe metformin when clinically appropriate.
What the FDA asked of manufacturers
The update page says the agency asked all companies manufacturing ER metformin to evaluate the risk of their product containing NDMA above the acceptable intake limit. It also asked them to test at-risk product before each batch is released onto the U.S. market.
An update on that page dated 6/11/2020 lists the voluntarily recalled ER metformin by company and lot. Its entries range from All lots to One lot to 14 lots. This guide does not name the companies. The page does.
What this does not tell you
The pages are marked 09/03/2020, 06/05/2020 and 01/06/2021, and the recall list is dated 6/11/2020. They report what the FDA stated as of those dates. They cannot tell a reader about any product on the market today, about any specific bottle, or whether any lot is affected now.
The cancer statements are the FDA's expectations about NDMA exposure, as worded on its pages. The FDA statement about immediate release products refers to its testing as of its page date.
What this guide says to do is only what the FDA pages say, attributed to the FDA. A licensed provider or pharmacist is the person to ask about a specific product or treatment.