On June 11, four more pharmaceutical companies announced a voluntary recall of extended-release (ER) metformin, a popular medication used to control type 2 diabetes. 

The recall comes after the U.S. Food and Drug Administration (FDA) found levels of N-Nitrosodimethylamine (NDMA) above the acceptable intake limit in certain lots, according to an FDA press release

NDMA is a contaminant linked to cancer. On May 29, MedTruth reported that Canadian drug company Apotex Pharmachem recalled its ER metformin. 

The FDA announced that Amneal, Marksans, Lupin and Teva have followed suit.

Teva Pharmaceutical Industries is headquartered in Petah Tikva, Israel, and Parsippany, New Jersey. The brand voluntarily recalled 14 lots of Metformin Hydrochloride Extended-Release Tablets in 500mg and 750mg, 100 and 1000-count bottles, in the United States June 2, making them the first company after Apotex to do so. Metformin sold by Teva is labeled as Actavis.

U.S.-based Amneal Pharmaceuticals released a statement on June 3 that the FDA identified unacceptable levels of NDMA in seven of its ER metformin lots. Amneal issued a recall not only for those lots, but for all 500mg and 750mg lots still within expiry.

Marksans Pharma, a Mumbai-based global company, announced a voluntary recall of one lot of metformin on June 8, the 500mg version from lot XP9004. Marksans’ metformin is labeled as Time-Cap.

Lupin Pharmaceuticals, an international brand also headquartered in Mumbai, voluntarily recalled lot G901203 of 500mg metformin on June 11, according to the FDA.

The recalls follow the discovery of unacceptably high levels of NDMA in the drugs. NDMA is sometimes found in drinking water that has been contaminated by industrial processes, according to the World Health Organization (WHO). The Centers for Disease Control and Prevention (CDC) found that NDMA has been observed in trace amounts in outdoor air, surface waters, soil, meat, and some household goods and beauty products.

NDMA is not thought to be harmful in small amounts, but WHO reports that NDMA is a “potent carcinogen” in animals exposed intentionally to very concentrated amounts and is “probably carcinogenic” to humans in high amounts as well. There are currently no reports of NDMA causing cancer in humans, however, and the CDC maintains that “exposure to NDMA does not mean that any effect on health will definitely occur." 

The FDA has not found evidence that immediate-release (IR) metformin products contain NDMA.

Levels of NDMA in metformin are under investigation. With repeated, long-term exposure, the contaminant may be carcinogenic.

Do not discontinue taking your medication without speaking to your doctor. Read the full press release here.