Metformin is the most popular diabetes drug in the world. At last count, nearly 90 million prescriptions are dispensed every year for this medicine. But last December the FDA announced that it was paying attention to metformin recalls outside the US. Other countries were reporting that some samples of metformin were contaminated with the probable carcinogen NDMA. This is the same nitrosamine that had contaminated a number of other drugs in prior years.
A year ago the FDA said it was investigating the problem:
“If as part of our investigation, metformin drugs are recalled, the FDA will provide timely updates to patients and health care professionals.”
In December, 2019, we wrote about our concerns with metformin at this link.
We noted that David Light, CEO of Valisure, reported that his New Haven, CT pharmacy was:
“having problems with metformin as well and have failed 60% of the batches we tested for concern over NDMA.”
Valisure tests every batch of medications it sells for contaminants.
It took until February, 2020, for the FDA to discover that the metformin contamination problem was not just a foreign problem. But the FDA wasn’t ready to take action. It kept putting out reassuring messages and telling patients to keep taking their metformin.
Turning up the Heat for Metformin Recalls:
On March 2, 2020, Valisure submitted a “Citizen Petition” to the FDA.
The pharmacy had:
“…tested and detected high levels of N-Nitrosodimethylamine (“NDMA”) in specific batches of prescription drug products containing metformin, a drug used to control high blood sugar in patients with type 2 diabetes…The carcinogenic nature of nitrosamines in general, and NDMA specifically, has been well documented in the scientific community since the 1960s…Furthermore, the presence of this probable carcinogen in a medication that is taken daily by adults and adolescents for a chronic condition like diabetes, makes this finding particularly troubling.”
Valisure reported that 11 drug companies were distributing batches of metformin above the FDA’s allowable NDMA limit. We were disappointed that the FDA did not respond promptly to take action. No metformin recalls were announced.
Valisure also provided a list of metformin products that passed its test. Here is a link to an article that includes that list.
When Did the FDA Take Action?
In May, 2020, Valisure published a report about nitrosamine contamination of metformin (medRxiv, May 26, 2020). Over one third of the samples the pharmacy tested had NDMA levels over FDA limits.
One day later the FDA admitted that it too had (Bloomberg, May 27, 2020):
“…discovered N-Nitrosodimethylamine, or NDMA, beyond acceptable amounts in some extended-release versions of metformin.”
In June the FDA posted information about extended-release metformin recalls on its website for two drug companies, Amneal and Apotex. Other companies that were caught up in the metformin recalls included Teva (metformin labeled as Actavis), Lupin and Marksans.
More Metformin Recalls:
In July the FDA announced additional recalls.
“This second round of voluntary recalls included Granules Pharmaceuticals (12 lots), Lupin Pharmaceuticals (now all lots), AvKARE (repackager for Amneal; all lots), PD-Rx Pharmaceuticals (repackager for Amneal; 31 lots and repackager for Marksans; 26 lots), the Harvard Drug Group (repackager for Apotex; one lot), and Preferred Pharmaceuticals (repackager for Marksans; four lots).”
But wait, it doesn’t end there. While everyone was focused on COVID-19, additional recalls were announced. Bayshore Pharmaceuticals had to pull some of its extended-release metformin in August.
In October, Marksans Pharma (under the label Time-Cap Labs) recalled more metformin. Sun Pharmaceuticals also pulled a lot of liquid metformin. The latest addition to the expanding list of metformin recalls involves Nostrum Laboratories.
We are too! Should you wish to look at the FDA’s list of metformin recalls, here is a link. It’s daunting, though. There are 254 entries. According to the FDA, the list is current as of 11/04/2020. Who knows how many more metformin recalls will occur during 2021?
You may wish to read an article that we posted awhile back that lists some of the metformin products that passed Valisure’s tests:
Which Metformin is OK and Which is on the FDA’s Problem List?
The FDA admits that several metformin diabetes formulations are contaminated with a probable carcinogen. Which metformin is OK? How would you know?
Readers React to Metformin Recalls:
Darlene was switched to an ineffective generic metformin:
“I was switched from one metformin generic company with a low level of contamination to another with no contamination. The new generic metformin does not work at all at keeping my blood glucose in check. Why would that occur since the generics are all supposed to be the same?
Darlene, you have discovered a dirty little secret that the FDA would prefer to ignore. We have discovered that not all generic drugs are created equal. Because you can measure your blood glucose, you can tell if a drug is working or not. I fear it is time to seek another metformin that 1) works and 2) is not contaminated with NDMA!
Kathy found a metformin that has no NDMA contamination:
“We sent a sample of my husband’s metformin to Valisure to be tested. It came back with 212 ng of NDMA. We then used their list of manufacturers that had low or no NDMA. Our doctor wrote a new prescription requesting a specific manufacturer.”
Richard bemoans all the contamination:
“Doesn’t it seem that the FDA is chasing a rabbit it cannot catch (i.e. metformin, Zantac). How many more?”
Paul was grateful for our warning about contamination:
“I want to thank you for your reporting on this problem. When I contacted my Walmart pharmacist he said that my doctor did indeed need to prescribe a replacement for my extended-release metformin due to possible tainted formulations that I had been dispensed.
“I don’t know how long it would have been unnoticed by my pharmacist, or doctor, if I hadn’t brought it to their attention, thanks to you.”
Sherry wonders about metformin and cancer:
“I am sure that more companies and more lots of the metformin will turn out to be tainted. My husband has been on the Amneal brand for years now. The last time it was reordered, CVS had a problem getting it. Last year they changed his metformin supplier and he got sick from that one, so we had to find the Amneal which we did. I knew that something was going on and the other day I got the FDA recall email that Amneal was on the list.
“A few years ago, after a kidney stone wouldn’t drop by itself, he had to go in for a procedure. Luckily they caught a small bladder cancer in time. I wonder if the bladder cancer has anything to do with the metformin contamination as they have no idea when it became tainted.
“I don’t trust any drugs any longer.”
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