Metformin Lawsuit Filed Over Cancer-Causing and Liver-Damaging Impurity

A generic metformin manufacturer faces a class action lawsuit brought on behalf individuals who purchased versions of the diabetes drug tainted with N-nitrosodimethylamine (NDMA); a chemical byproduct of the manufacturing process that is known to cause cancer and liver damage.

The complaint (PDF) was filed by Luis Sandoval in the U.S. District Court for the Central District of California on June 29, seeking class action status for claims against Heritage Pharmaceuticals, which was doing business as Avet Pharmaceuticals, Inc..

Sandoval, of California, has been taking metformin for the treatment of his diabetes since at least 2010. However, he only learned of the presence of high levels of NDMA in Avet’s generic metformin formulation earlier this year, when it was publicly reported that several versions of metformin may contain the cancer-causing and liver-damaging impurity.

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Zantac Lawsuits

Side effects of Zantac may increase the risk of cancer, due to chemical impurities found in the heartburn drug.

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NDMA is considered a human carcinogen, and has been found to contaminate other pharmaceutical drugs to manufacturing or design problems. A number of Zantac recalls and valsartan recalls have been issued over the past few years, after dangerously high levels of NDMA were detected in the popular heartburn and blood pressure medications, and users reported developing stomach cancer, bladder cancer, liver cancer and other injuries following long-term use.

Late last year, reports first warned about the potential risk of metformin NDMA contamination problems, after some versions of the drug sold outside the United States tested positive for the chemical, raising concerns that metformin recalls may be necessary. However, the FDA indicated at that time that testing of products distributed in the U.S. found that the NDMA levels in metformin were undetectable or below federal limits for exposure to the chemical.

In March, the independent online pharmacy Valisure filed a citizen’s petition urging the FDA to issue metformin recalls, after independent testing found levels of NDMA in certain pills was higher than the agency’s recommended daily exposure threshold of 96 nanograms.

Specifically, Valisure found that Avet’s formulation of metformin contained 5.3 to nine times higher than the FDA’s recommended daily exposure limit, according to the lawsuit. To date, Avet has not issued a recall for its metformin products.

“Avet had not yet issued a recall of its defective metformin and continues to represent on its website that it manufactures ‘high quality generic medicines’,” Sandoval’s lawsuit states. “However, these representations are false, as Defendant’s metformin medication contains the carcinogenic impurity NDMA.”

Sandoval’s lawsuit seeks to have Avet reimburse purchasers of the drug for the money they paid, expecting a defect-free product, indicating he himself has paid a $35 per month copay since 2010. He presents claims of breach of warranty, unjust enrichment, fraudulent concealment, fraud, conversion, and violation of the California Unfair Competition Law.

NDMA In Zantac and Valsartan

Valisure is the same pharmacy which first raised alarms about the link between Zantac and cancer in September 2019, after finding that some pills contained 3,000,000 ng of NDMA. This led to further FDA testing, which confirmed the high levels were present in virtually all Zantac products and their generic equivalents, resulting in a widespread, and still ongoing, Zantac recall.

Concerns over NDMA drug contamination in pharmaceutical drugs began to emerge in 2018, with an investigation into a number of generic blood pressure drugs that were found to contain high levels of the chemical. This led to several rounds of recalls for valsartan, losartan and irbesartan, and investigations suggested that NDMC may have contaminated the drugs as a by-product of changes in the generic drug manufacturing process.

In response to concerns about the cancer risk with valsartan and other similar drugs, and the possibility of shortages for the hypertension drugs, the FDA established a permissible daily limit for NDMA at 96 nanograms, requiring pills that may expose users to more of the carcinogen to be recalled.

While drug makers and federal regulators indicate they are continuing to investigate the underlying cause of both the NDMA contamination, many consumers diagnosed with cancer in recent years are now pursuing valsartan lawsuits and Zantac lawsuits, alleging they may have avoided a cancer diagnosis if other treatments had been used.

15 Comments

  • DexterAugust 24, 2023 at 8:11 pm

    I have been taking metformin for years, I am guessing but probably since the 90,s. The metformin that was being prescribed increased to 500mg before I realized it was effecting my kidneys and liver. I am now on the list for liver transplant . My liver is dying due to the overuse of metformin. I wish and pray that God will send someone to help. Financially the debt from all the test and doctors has[Show More]I have been taking metformin for years, I am guessing but probably since the 90,s. The metformin that was being prescribed increased to 500mg before I realized it was effecting my kidneys and liver. I am now on the list for liver transplant . My liver is dying due to the overuse of metformin. I wish and pray that God will send someone to help. Financially the debt from all the test and doctors has poor house. As the gentleman above asked “ Is there a class action lawsuit against the makers of this killer drug

  • MicaelaJune 5, 2023 at 3:40 am

    After taking metformin for years and apparently my LFT levels were high and my Dr. Didn't pay attention to it and now I have cirrhosis of the liver. I am currently waiting for my biopsy to come back to see if it is cancerous. Prior to taking this medication I never had any liver problems

  • CarolynMay 31, 2023 at 12:24 pm

    My mom was just diagnosed with liver failure and she's been taking metformin

  • ThomasMay 17, 2023 at 8:16 am

    I was put on metformen around 2018 and have been told I have cirrhosis of the liver F4 ? I drink very little. I had to take some steriods for my foot and they tested my liver while I did the treatment for 6 weeks and had no problems then. My Dr. still has me on this drug. Should I be taking it now? I would think they have fixed this. I even have a thyroid problem now. May not be related but who k[Show More]I was put on metformen around 2018 and have been told I have cirrhosis of the liver F4 ? I drink very little. I had to take some steriods for my foot and they tested my liver while I did the treatment for 6 weeks and had no problems then. My Dr. still has me on this drug. Should I be taking it now? I would think they have fixed this. I even have a thyroid problem now. May not be related but who knows.

  • EugeneApril 30, 2023 at 2:55 pm

    I've used metformin for 20 years and now have stage 3 kidney cancer. Is there a class action lawsuit? If so, how do I join it?

  • LucretiaMarch 17, 2023 at 8:11 pm

    I have been taking metformin for 20 years now. I felt as though it wasn't working and stopped it on my own for awhile. My doctor scolded me on more than one occasion. So finally I gave in. I started taking it religiously. I was diagnosed with NAFL cirrhosis with ascites back in August. However I feel this could have been avoided if the doctors had been honest. They are the link between the do's an[Show More]I have been taking metformin for 20 years now. I felt as though it wasn't working and stopped it on my own for awhile. My doctor scolded me on more than one occasion. So finally I gave in. I started taking it religiously. I was diagnosed with NAFL cirrhosis with ascites back in August. However I feel this could have been avoided if the doctors had been honest. They are the link between the do's and don't of our medication.

  • KarenMarch 10, 2023 at 4:48 pm

    I was taking metformin until April of 2022 and was taking metformin for a few years and now I have liver damage to taking metformin. This medication should have been recalled a long time ago and the drug company needs to remove the medication permanently.

  • CrystalNovember 26, 2022 at 11:51 pm

    We are losing a dad grandad and great grandad to this medicine. We now have just days left with him. He has never drank a drop of alcohol his whole life this medicine gave him cirrhosis if liver and he does not deserve to die and be take from us this early for metformin.

  • ShannonNovember 15, 2022 at 3:55 pm

    My Mother was a diabetic since the 80s and was on metformin. She recently passed away of bile duct cancer, which is a form of liver cancer. It was all over her liver. She did not have a liver disease nor did she drink alcohol.

  • AliciaJuly 3, 2022 at 12:30 am

    I ended up with ketoacidosis, kidney damage, and liver damage

  • JamesFebruary 11, 2022 at 12:42 am

    I’m a 53 year old U.S. Navy Veteran and was prescribed 1000mg of metformin for years. I recently was diagnosed with stage 3 liver disease. Please advise.

  • DavidFebruary 22, 2021 at 10:36 pm

    I have been only taking Avet Metformin for a few months because I mistakenly decided to let Humana deliver my meds, which they are incompetent at it turns out. My biggest problem though is that since taking Avet Metformin my fasting blood sugar has started rising and has gone from about 140 to 150 every morning to 190 up to 216 this morning. In the past two weeks I have lost 5 pounds hoping maybe [Show More]I have been only taking Avet Metformin for a few months because I mistakenly decided to let Humana deliver my meds, which they are incompetent at it turns out. My biggest problem though is that since taking Avet Metformin my fasting blood sugar has started rising and has gone from about 140 to 150 every morning to 190 up to 216 this morning. In the past two weeks I have lost 5 pounds hoping maybe it was that gain from the holidays, which start October 14th in my family with the first of 4 birthdays, our anniversary, Thanksgiving, Christmas and ends on Valentines Day. I believe they are corrupt. I do not need to sue them, just find a different supplier.

  • GregDecember 16, 2020 at 9:39 pm

    I took metformin from 2013-2018 and developed stomach cancer as a result.

  • WadehahOctober 12, 2020 at 4:26 pm

    I take metformin tab 1000mg for years. Has this medicine been recalled or the patients notified personally about it from the pharmacies? I need to know ASAP.

  • DelSeptember 28, 2020 at 8:22 pm

    I have been newly prescribed and issued Metformin Tab 500MG, which is manufactured by AVET PHARMA. Reading this indicates there has not been a recall by the FDA (no surprise here). Was this quality breech widespread and has the production process been corrected?

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