Two makers of metformin—Marksans Pharma and Sun Pharmaceutical Industries—are recalling their extended release (ER) formulas of the drug because they contain quantities of N-nitrosodimethylamine (NDMA) that exceed the acceptable intake limit, as established by the U.S. Food & Drug Administration (FDA).

Metformin is a drug that physicians prescribe to control high blood sugar in patients suffering from type 2 diabetes. In June 2020, the FDA announced results of its extensive laboratory analysis of the drug, revealing products in which NDMA levels exceeded 96 nanograms, the amount considered reasonably safe for human digestion over a lifetime of exposure.

Both the U.S. Environmental Protection Agency (EPA) and the World Health Organization’s International Agency for Research on Cancer (IARC) have classified NDMA as a substance that could cause cancer in humans. As an environmental contaminant, the substance is known to exist in water, as well as a variety of foods—from meats and vegetables to dairy products.

More on the Recalls

Marksans’ June 2020 recall was expanded on October 2, 2020, to include 76 unexpired lots of Time-Cap Labs, the company’s 500 mg, and 750mg metformin ER tablets.

On September 23, 2020, Sun Pharmaceuticals recalled a single lot of RIOMET ER, metformin hydrochloride for extended release oral suspension (500 mg per 5 mL).

Both companies’ announcements about their recalls inform distributors and retailers to stop their distribution and sales of the drug and return it to wherever they purchased it.

The announcements also instruct patients who take the metformin medications to continue taking them, as they put themselves at risk of danger by quitting without first talking to their medical provider. Patients should contact their doctor or pharmacist about finding an alternative medication.

Possible Injuries Associated With NDMA

NDMA forms naturally, and it also occurs as a by-product of certain manufacturing processes. As a probable human carcinogen, the substance has been linked to several cancers:

  • Prostate cancer
  • Leukemia
  • Stomach cancer
  • Kidney cancer
  • Bladder cancer
  • Esophageal cancer
  • Non-Hodgkin’s lymphoma
  • Multiple myeloma
  • Colon/colorectal cancer
  • Liver cancer
  • Pancreatic cancer

Individuals who have experienced adverse reactions or quality problems experienced with the use of either the Marksans or the Sun metformin products can report the incidents to the FDA’s MedWatch Adverse Event Reporting program either online, by regular mail or by fax.

Legal Actions

In the spring of 2020, an Indiana woman filed a class-action lawsuit against metformin maker Granules Pharmaceuticals. The case was filed in the U.S. District Court for the District of New Jersey.

Many people throughout the U.S. are prescribed metformin. The drug is manufactured and distributed by dozens of companies. Brand names connected with the medication include Glucophage, Glucophage XR, Fortamet, Riomet, and Glumetza, as well as well as generic forms.

Other companies that make metformin medications in which the FDA has detected dangerous levels of NDMA include:

  • Granules Pharmaceuticals: 12 lots
  • Lupin Pharmaceuticals: All lots
  • Avkare (Amneal packager): All lots
  • Apotex: All lots
  • Amneal: All lots
  • Marksans (labeled as Time-Cap): One lot (XP9004)
  • Teva (labeled as Actavis): 14 lots
  • PD-Rx Pharmaceuticals (Amneal repackager): All lots
  • PD-Rx Pharmaceuticals (Marksans repackager): All lots
  • The Harvard Drug Group (Apotex repackager): One lot (T-02134)
  • Preferred Pharmaceuticals (Marksans repackager): Four lots (J0119M, K1419L, K2719J, A0220H)
Sara Stephens is a freelance writer who has developed a hefty portfolio of work across several industries, with a strong emphasis on law, technology, and marketing. Her work has appeared in the New York Times, as well as various technology and consumer publications, both print and online. Sara also works as a freelance book editor, having developed and edited manuscripts for bestselling and novice authors alike, and as a verbal strategist for a Miami branding consultancy.