Disclaimer: I am not a physician, biochemist, employed by a pharmaceutical company or in any other way connected to any entity which would cause me to make money by convincing you to take/not take this drug. I am only reporting information I have found on the internet from reputable sources to help you make an informed decision about your own healthcare. Consult your doctor or pharmacist if you have additional questions or concerns.
There seems to be some misinformation on the internet and spreading by word of mouth about Metformin. I would like to try to clear this up for those of you who currently take Metformin, have loved ones who take Metformin, or those who may be considering it as part of their treatment. Metformin is a valuable drug to fight Type 2 diabetes and the first drug that most physicians prescribe for patients newly diagnosed with Type 2 diabetes since it is inexpensive and well tolerated by most patients.
Where It Comes From
Metformin is derived from the Galega officinalis (also known by many other names including as goat's rue, false indigo, professor-weed, French lilac and Italian fitch). It is a summer-flowering perennial herb with white, blue or purple flowers found in most temperate regions. It originated in southern Europe and western Asia, but in the last two centuries it has spread to many countries around the globe.
As far back as the Middle Ages, it was used in folk medicine to relieve the frequent urination accompanying the disease that is today known as diabetes mellitus. The plant was also given as a medicine in plague epidemics to promote perspiration of the affected individuals.
Modern History as an Oral Diabetes Treatment
Studies found Galega officinalis to be rich in guanidine, which, in 1918, was shown to lower blood glucose. Guanidine derivatives were synthesized and some (not metformin) were used to treat diabetes in the 1920s and 1930s but were discontinued due to toxicity and the increased availability of insulin.
Later chemists found that they could make the compound more tolerable by bonding two guanidines together, forming a biguanide. Metformin is one such biguanide, first synthesized in 1929 and then clinically developed in the late 1950s by the French physician Jean Sterne, who gave it its first trade name, Glucophage ("glucose eater").
In 1957, Metformin was studied in several trials in Paris and was shown to lower blood glucose in patients with type 2 diabetes, although not in healthy individuals. Unlike sulfonylureas (another class of oral antidiabetic drugs), Metformin did not stimulate insulin release, but primarily reduced the release of glucose from the liver.
Over the next few decades, studies about Metformin's safety and efficacy trickled in, but it wasn't until the landmark United Kingdom Prospective Diabetes Study (1977 to 1997) that Metformin gained the renown that it enjoys today.
The Food and Drug Administration formally approved Metformin in 1994, assuring that Americans could have access to this rising star of diabetes care. In 2002, Metformin became available as a generic medication, making it one of the least expensive diabetes treatments.
Metformin is considered the first line of defense for people with the condition, as it is safe, effective, and affordable. It’s not linked to weight gain and it puts very little stress on the internal organs. The American Diabetes Association includes it in its diabetes Standards of Care.
Metformin is now also used to treat polycystic ovary syndrome, gestational diabetes and is showing early promise as a treatment for cancer.
How It Works
Metformin does not increase insulin levels in the body, but instead lessens the amount of sugar the body produces and absorbs. As it lowers glucose production in the liver, it also lowers blood sugar by increasing the body’s sensitivity to insulin. It also decreases the amount of glucose that can be absorbed from food that is eaten.
There are side effects with Metformin, but many of these are mild, and are associated with taking the medicine for the first time. Nausea and gastric distress such as stomach pain, gas, bloating, and diarrhea are somewhat common among people starting up on Metformin. It’s common for doctors to start patients on a low dose and build the dosage up over time, starting with 500mg and building up over a few weeks. Using the extended release version of Metformin can help keep these symptoms at bay.
Metformin is sold in the US under the brand names Fortamet, Glucophage, Glucophage XR, Glumetza and Riomet. It is available in the following dosage forms:
- Tablet, Extended Release
- Suspension, Extended Release
- Tablet
- Solution
- Tablet, Extended Release, 24 HR
The most common strengths found are 500mg, 750mg, and 1000mg.
Here’s where the controversy starts
In December 2019, the FDA announced it was aware of certain Metformin products overseas that were contaminated with low levels of NDMA.
NDMA is the same carcinogen that led to the recall of Zantac. It’s a common contaminant in water and grilled or cured meats. In other words, most people are exposed to low levels of NDMA. NDMA can enter drugs during the manufacturing, packaging, or storage process. It’s suspected that long-term exposure to more significant amounts can be dangerous, leading to symptoms like jaundice, nausea, fever, and ultimately liver damage or lung cancer.
Just a few months later, in February 2020, the FDA said initial lab analyses of certain domestic Metformin products did in fact show traces of NDMA in some samples. At that time, however, the agency wasn't recommending any measures be taken.
Several labs have voluntarily recalled their Metformin. You can read all the press releases here.
On Jan. 4, 2021, the FDA announced that the recall extends to additional manufacturers, forms, and dosages. Eleven companies have now voluntarily withdrawn 500 mg, 750 mg, and 1000 mg extended-release metformin tablets and extended-release metformin oral suspension:
- Amneal Pharmaceuticals
- Apotex Corp
- AVKARE Inc. (Amneal)
- Bayshore Pharmaceuticals, LLC
- Denton Pharma, Inc. (Marksans)
- Direct Rx (Marksans)
- Granules Pharmaceuticals
- Lupin Pharmaceuticals
- Marksans Pharma Limited
- Nostrum Laboratories, Inc.
- PD-Rx Pharmaceuticals (Amneal)
- PD-Rx Pharmaceuticals (Marksans)
- Preferred Pharmaceuticals, Inc. (Marksans)
- RemedyRepack Inc. (Marksans)
- Sun Pharmaceuticals Industries, Inc.
- Teva Pharmaceuticals
The complete list with lot number and expiration dates can be found here.
www.fda.gov/drugs/drug-safety-and-availability/search-list-recalled-metformin-products
Please note that Metformin has not been “banned” and it is not illegal to prescribe or dispense it. Some types from some manufacturers have been voluntarily recalled. It is not every kind of Metformin or every strength.
If your healthcare provider would like you to start taking Metformin you should not be concerned.
Based on the FDA guidelines, in the case of a patient-level recall, action is immediately taken at pharmacies around the country to remove the affected products from distribution and notify any patients who may have the drug at home.
What You Can Do
If you already take Metformin, don’t stop taking it. It is very unlikely that the medication you are taking is on the recall list and stopping your medication abruptly can have serious consequences. While many over-the-counter drugs can be discontinued at will, prescription drugs like Metformin that are critical to maintain health should be taken until your doctor finds a replacement for you if needed.
Check the recall list. If your medication bottle does not list the manufacturer or lot number contact the pharmacy where you get your prescriptions for that information.
Contact the manufacturer. Manufacturer contact information is usually listed in the FDA recall announcement or on the manufacturer’s website.
Contact the FDA. You can contact the FDA’s Center for Drug Evaluation and Research (CDER) with any questions or concerns at druginfo@fda.hhs.gov or through the following toll-free numbers: 1-855-543-3784 or 1-310-796-3400.
If you are still concerned with the safety of your Metformin, you can discuss where your Metformin is coming from with your pharmacist, although no pharmacies should be distributing any tainted medication. If you have any lingering concerns, you can ask your healthcare provider to temporarily switch you to an immediate-release metformin product instead, as none of these formulations have been recalled.
The big takeaway: Metformin is still a safe, inexpensive and effective drug for the treatment of diabetes. Don’t automatically rule it out because of something you heard.