RELATED: The Possible Benefits of Metformin for Type 2 Diabetes and Other Health Conditions Here are seven things you need to know if you or a loved one has been prescribed metformin as part of a type 2 diabetes treatment plan.
1. Which Batches of Metformin Are Affected by the Recall?
Certain batches of metformin-ER are being recalled, and the FDA hasn’t indicated that metformin-IR, the most commonly prescribed type of the drug, is impacted. As the American Academy of Family Physicians (AAFP) notes, the recall impacts roughly 19.5 million prescriptions, or one-quarter of all metformin drug prescriptions, which average 78 million annually, according to a 2017 report from the Agency for Healthcare Research and Quality. Robert Gabbay, MD, PhD, chief scientific and medical officer for the American Diabetes Association (ADA), estimated that these numbers are likely similar in 2020, though he noted the ADA does not track metformin prescription trends. Jeremy Kahn, a spokesperson for the FDA, said the agency does not have information on the percentage of metformin-ER inventory affected by the recall. “Metformin-ER is not in shortage,” he added. You can see the full list of recalled metformin-ER at the FDA website. RELATED: Type 2 Diabetes Meds May Not Prevent the Disease in People With Prediabetes
2. What Should I Do if I Take Metformin to Manage Diabetes?
Check to see if your metformin is part of the recall. If it is, don’t abruptly stop taking your meds without speaking with your doctor first, the FDA urges in an October 2020 statement. Doing so can send your blood sugar soaring, and that is risky in and of itself. “Patients should continue to take their metformin until their pharmacist supplies a different manufacturer’s product or their doctor prescribes a different treatment,” says Matt Petersen, vice president of medical information and professional engagement for the ADA, in an official release. As for what to expect when you contact your provider? It’ll depend on your individual health, but he or she may prescribe a different med that is not affected by the recall or potentially metformin-IR. “The solution in this instance is quite simple,” says Caleb Alexander, MD, the codirector of the Johns Hopkins Center for Drug Safety and Effectiveness in Baltimore: “Patients can simply be switched to a shorter-acting formulation.” Dr. Gabbay agrees, noting that a switch to metformin-IR is possible because it regulates blood sugar the same way metformin-ER does. “ER can reduce side effects in some patients (stomach upset, diarrhea) compared to regular metformin, though in all patients those side effects tend to reduce with time,” Gabbay says. “Dosing of ER versus IR is somewhat different, so again, a switch must be managed by a patient’s primary care provider.”
3. What’s the Difference Between Metformin-IR and Metformin-ER?
Metformin-IR, which is sold under the brand name Glucophage, is generally split up throughout the day, though you may take only one dose per day to start, notes the discount drug website GoodRX. On the other hand, metformin-ER, which is sold under the brand name Glucophage XR, is often taken one time per day (however, in some cases, your doctor may okay splitting up dosing). It depends. Check the bottle to learn which type of metformin you’re taking. Metformin is sold under several brand names, not only Glucophage:
Metformin-IR Brand Names
GlucophageRiometEqv-FortametEqv-Glumetza
Metformin-ER Brand Names
Glucophage XRRiomet ERFortametGlumetzaEqv-Glucophage XR
RELATED: How to Know if SGLT2 Inhibitors Are Right for Your Diabetes Treatment Plan
4. What Is NDMA and Why Might Exposure to It Be Harmful?
NDMA is a chemical that has been associated with liver damage in humans, and animal studies have linked exposure to an increased risk of cancer and stillbirths, according to the Centers for Disease Control and Prevention (CDC). The chemical was once used to make rocket fuel, and is still sometimes produced as a byproduct of a variety of manufacturing processes, including the production of medicines, according to the CDC. Kahn, the FDA spokesperson, said that the agency “has no information to provide on specific adverse events being linked directly to NDMA impurities.” NDMA is classified as “probably carcinogenic to humans” by the International Agency for Research on Cancer. But that doesn’t mean you should panic. More on this later.
5. How Did Metformin Become Contaminated With NDMA?
The short answer is: Regulators still don’t know, though the cause under ongoing investigation, according to the FDA. They are asking all manufacturers of ER metformin — including companies not covered by the current recall — to test batches for NDMA before selling these drugs in the United States. The FDA says it does not know how long NDMA has been present in the recalled metformin. RELATED: Does Metformin Cause Weight Loss? What to Know Before Trying It
6. Is My Cancer Risk Higher if I’ve Been on Metformin-ER for a While?
Probably not, but it’s not certain. The FDA recalled certain batches of metformin after finding levels of NDMA “above the acceptable intake limit,” which is 0.096 micrograms. Scientific research has produced mixed results on whether NDMA poses a cancer risk in humans, says Thomas Marron, MD, PhD, an assistant professor in oncology at Mount Sinai in New York City and a medical reviewer for Everyday Health. While preclinical studies have suggested that NDMA exposure may elevate cancer risk, larger population studies in humans, such as a September 2018 study in the BMJ, have suggested that NDMA does not cause cancer in humans, Dr. Marron says. Health agencies including the FDA and the World Health Organization’s (WHO) International Agency for Research on Cancer also note that the levels in medicines contaminated with NDMA likely don’t contain enough of this impurity to cause cancer in humans. What’s more, the FDA says it doesn’t expect NDMA to be harmful at low levels, even when someone is exposed over a long period of time, such as 70 years. The agency notes that samples of the contaminated metformin appear to have similar NDMA concentration to that of grilled and smoked meats. Most often, people are exposed to NDMA by consuming these foods, along with cheese, or fermented foods like beer, according to the CDC. Certain cosmetics and cleaning products may also contain NDMA. Whether NDMA poses a cancer risk from these consumer items is also uncertain, Marron explains. “It’s (NDMA) in foods like beer, cheese, smoked meats, all things associated with Western diets where there are higher rates of cancer in general,” he says. “It’s very difficult to parse out the different contributing factors, even when you have large data sets,” such as in the aforementioned BMJ study.
7. What if I’m Taking a Form of Metformin-ER Not Covered by the Recall?
You should continue to check the list of recalled metformin on the FDA’s website to ensure your medication is safe to use. After all, the number of companies and batches of metformin-ER covered by recalls in the United States have been expanding. If your drug isn’t there now, you can check back later to be sure it isn’t added in the future. You should also check with your pharmacy to see how they would notify you if the batch of metformin-ER you’re prescribed gets added to recall lists.
