Popular Diabetes Drug Metformin contains Carcinogen – FDA  


(May 28, 2020) – A popular diabetes drug, Metformin, has been found to contain a carcinogen, says the FDA, which made the announcement yesterday. Metformin – the active ingredient and also the drug’s generic name – is an oral medication meant to help control blood sugar levels in those with type 2 diabetes. Metformin is sometimes used together with insulin or other medications, but it is not meant for treating type 1 diabetes.

U.S. regulators are contacting pharmaceutical companies that make Metformin after some of the pills the FDA examined were found to contain high levels of a chemical linked with cancer.

NDMA in Metformin

The FDA discovered N-Nitrosodimethylamine, or NDMA, beyond acceptable amounts in some extended-release versions of metformin, an agency spokeswoman, Sarah Peddicord, told Bloomberg News. The World Health Organization (WHO) classifies NDMA as a probable human carcinogen.

21 Million Prescriptions in 2019

People diagnosed with type 2 diabetes take metformin to control high blood sugar. Some 21 million prescriptions for metformin’s extended-release version were written in the U.S. last year, according to Bloomberg. That total accounts for roughly a quarter of metformin prescriptions handed out around the world.

Bloomberg reported that some metformin recalls are expected as soon as this week; however, it wasn’t clear which companies were planning to remove their products from pharmacy shelves. Metformin is made for the U.S. market by several generic drugmakers around the world.

“We cannot confirm or deny a recall action before it has taken place,” said Ms. Peddicord.

Immediate-release Version Problematic

She also said the agency hasn’t found elevated NDMA levels in immediate-release metformin. She advised patients not to stop taking the drugs without first consulting their healthcare providers.

The FDA began investigating metformin in December 2019 after some versions of the medication sold in other countries were found to be contaminated with NDMA. In February 2020, the agency said it hadn’t found NDMA in excess of acceptable limits.

Metformin would be the third popular medication in recent years to face recalls related to NDMA. The agency also issued warnings about finding NDMA in Zantac (also sold under the name ranitidine), recalling the drug on April 1, 2020. The agency determined that the chemical makeup of the human stomach can cause NDMA to form and increase when stored at high temperatures.

NDMA Recalled July 2018

Beginning in July 2018, the FDA recalled millions of blood-pressure pills known as angiotensin II receptor blockers after they were found to be contaminated with NDMA during the manufacturing process, mostly at factories in China and India. The U.S. Senate Finance Committee is planning to hold a hearing next week to examine the FDA’s ability to adequately inspect drug-production facilities overseas.

Valisure Raised Red Flags

Valisure, an online pharmacy which tests all the drugs it sells, had raised red flags about NDMA in Zantac in September 2019. Valisure pressed the FDA then for recalls. The agency responded by questioning Valisure’s testing methods.

In March 2020, Valisure analyzed regular and extended-release metformin, finding that NDMA exceeded acceptable limits in versions made by Amneal Pharmaceuticals LLC, Aurobindo Pharma Ltd. and Lupin Ltd., among other companies. Valisure again pressed the FDA to conduct recalls.

Amneal, Aurobind and Lupin did not respond to Bloomberg’s requests for comment.

In a report posted May 26, Valisure analyzed metformin sent to it by people around the U.S., finding that 36% of 128 samples contained levels of NDMA that exceeded daily limits set by FDA as acceptable.

“The presence of this carcinogen in metformin where multiple tablets can be taken daily and often for a lifetime diabetic condition, makes this finding particularly concerning,” Deanna Akinbajo, chief pharmacist at Valisure, said in a statement.

Metformin was recalled in Singapore late last year and in Canada earlier this year because of concerns about NDMA contamination.