Suspected carcinogen drives yet another metformin recall, this time by Missouri-based Nostrum Labs

Since the FDA noticed a possible carcinogen in popular diabetes med metformin earlier this year, the list of companies recalling their versions has just kept growing.

Monday, Nostrum Laboratories said it’s voluntarily recalling two lots of its 750-mg extended-release metformin tablets because samples found higher-than-allowed levels of N-nitrosodimethylamine (NDMA).

The Missouri company didn’t disclose the exact number of bottles involved in the recall, and a Nostrum spokesperson didn’t immediately respond to a request for comments. According to the FDA, the lots contain packages of 100 metformin tablets each.

Nostrum Labs’ move marks the latest in a series of metformin recalls because of potentially cancer-causing impurities.

The FDA first noticed abnormally high levels of NDMA in samples of extended-release metformin in May. Recalls immediately ensued. The first round came from generics players Apotex, Amneal, Lupin, Marksans and Teva.

RELATED: Marksans expands metformin recall as carcinogen contamination worries continue to grow

Lupin in July pulled all remaining lots of its extended-release metformin after discovering high levels of NDMA in samples. Marksans first only targeted one lot of 500-mg pills at the request of the FDA but last month yanked an additional 76 lots covering different package sizes.

The list has grown even larger since then.

Virginia-based Granules Pharmaceuticals has a recall of 12 lots on the FDA’s record.  In August, New Jersey-based Bayshore Pharmaceuticals pulled one lot each of its 500-mg and 750-mg metformin tablets. India’s Sun Pharma joined in September, recalling one lot of its Riomet ER containing 747 bottles of the metformin product off the U.S. shelves.