The Food and Drug Administration (FDA) has contacted five manufacturers of metformin-containing extended-release products to recommend that they voluntarily recall products that contain levels of the nitrosamine impurity N-nitrosodimethylamine (NDMA) above the agency’s acceptable intake limit. NDMA is considered a probable human carcinogen. The FDA’s acceptable intake limit in drug formulations is 96 nanograms of NDMA per day.
Recalls will be listed on the FDA webpage. As of May 29, there was one recall of all lots of metformin hydrochloride extended-release tablets, USP 500 mg, from Apotex Corp. One lot of the medication was found to have excessive levels of NDMA. The affected product is packaged in containers of 100 tablets and labeled with NDC number 60505-0260-1. Report adverse reactions or quality problems experienced with the use of this product to the FDA’s MedWatch Adverse Event Reporting program, https://bit.ly/FDAmedwatch.
According to an FDA press release, physicians should continue prescribing metformin, which is used to control high blood sugar in patients with type 2 diabetes, when clinically appropriate.
NDMA has not been found in immediate-release metformin products. Elevated levels of NDMA have been found in some finished-dose tablets of the extended-release formulation, but NDMA has not been detected in samples of the metformin active ingredient. The source of NDMA can be related to a drug’s manufacturing process, chemical structure or the conditions in which the drug is stored and packaged.
