Yet Another Recall For Popular Diabetes Drug Metformin Over Possible Cancer Risk — What You Need to Know

The call from the FDA came after a high level of a contaminant called N-Nitrosodimethylamine (NDMA), which is linked to cancer, was found in some versions of the drug. NDMA was found in several batches of the extended-release form of the drug, which is often prescribed to control high blood sugar in patients with type 2 diabetes. However, metformin in its immediate-release form — which is prescribed more often for people with diabetes than the extended-release — was not found to contain an unsafe level of NDMA, and is not a part of this recall.

After the FDA’s initial announcement, SurvivorNet consulted Dr. Marilyn Tan, chief of the Stanford Endocrine Clinic, to get some information about how worried patients should be. She explained that this recall doesn’t apply to most patients who are on metformin.

"Metformin is the most commonly used drug for type 2 diabetes and it's one of the most cost-effective," Dr. Tan said. "…for the vast majority of patients, this recall doesn't apply to the type that they are on."

Even for diabetes patients who are currently on the type of metformin that is being recalled, Dr. Tan stressed how important it is to continue taking the drug until a replacement can be prescribed. Many patients who currently take the extended-release form of metformin, Dr. Tan said, may be able to switch to the immediate-release form of the drug with few issues.

"In terms of medication efficacy, they're both equally effective," Dr. Tan said. “[Those] who are on extended release, they should contact their providers first. Stopping could cause risks like high blood sugar.”

What Do People on Metformin Need to Know About Cancer Risk?

NDMA, the chemical found in the extended-release form of metformin that led to the recall, can be unintentionally formed during various manufacturing processes, according to the Centers for Disease Control and Prevention (CDC). People can be exposed to low levels of NDMA in a variety of ways it can be found in foods like cured meats and fish, beer, tobacco smoke and even in some toiletry and cosmetic products. NDMA is labeled as a "probable carcinogen," meaning it may cause cancer in humans. However, in low levels, it’s considered safe — and NDMA is all around us at low levels.

When it comes to cancer risk, it's difficult for medical professionals to say exactly how dangerous the substance is.

"We don't really know long term exactly what the risk is … we do know that there is some potential for cancer and liver issues," Dr. Tan explained.

The FDA considers the chemical generally safe as long as exposure does not exceed a certain limit and people are not exposed for a long period of time.

To avoid potential dangers, the FDA regularly tests and monitors products like medications to ensure that they only contain what the agency considers to be safe levels of contaminants like NDMA. Earlier this year, the agency recalled popular heartburn drug Zantac over high NDMA levels. This new metformin recall comes after the agency determined that the extended-release form of the drug had NDMA levels that were above the FDA's "acceptable intake limit."

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