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The Pros and Cons of Metformin for Diabetes

Millions of people pop metformin for diabetes every day. It's the world's most popular diabetes drug. Did you know this amazing med came from mother nature?

Metformin is #7 on the doctors’ hit parade of top 10 prescription drugs. Each year the number of prescriptions increases substantially. Last year there were 87 million metformin prescriptions dispensed in U.S. pharmacies. That does not count combo products that include metformin in their formulation such as Glucovance, Invokamet, Janumet, Kombiglyze XR, Metaglip and Synjardy, to name just a few. Metformin is clearly the #1 drug for diabetes and because the number of people with diabetes keeps going up, prescriptions for metformin are skyrocketing. That’s why readers of our syndicated newspaper column and visitors to this website are so desperate to learn more about metformin for diabetes.

How To Know If Metformin  for Diabetes Is Right for You:

Here is a typical letter from a reader:

Q. I crossed the line a month ago from normal blood sugar to type 2 diabetes and was put on metformin. I hate taking drugs. What can you tell me about metformin?

Thank the Old Wives:

A. Metformin is one of the oldest and most well-studied diabetes medicines. It probably comes as a shock to most prescribers to learn that their favorite diabetes drug is available thanks to the old wives.

Practitioners of folk medicine discovered that French lilac (Galega officinalis) helped control the symptoms of a condition associated with “sweet urine.” An article in the Journal of Clinical Investigation (Oct. 15, 2001) noted:

“In medieval times, a prescription of Galega officinalis was said to relieve the intense urination accompanying the disease that came to have the name of diabetes mellitus [now known as type 2 diabetes].”

The botanist and physician Nicholas Culpeper detailed the health benefits of French lilac in 1656. He described the ability of the plant to lower blood sugar and control some symptoms of diabetes, such as excessive urination.

The Discovery of Metformin for Diabetes:

Ingredients in French lilac, guanidine and galegine, were thought to be the active compounds that helped control blood sugar. It wasn’t until 1957 that the French physician and clinical pharmacologist, Dr. Jean Sterne, isolated metformin for diabetes. He called it Glucophage, roughly translated as “glucose eater.”

That same year (1957), French physicians began prescribing metformin for diabetes. The drug was approved by Canadian regulators in 1972. It wasn’t until 1994 that the U.S. Food and Drug Administration gave the drug a green light. Doctors began prescribing it in 1995 under the brand name Glucophage.

The Pros and Cons of Metformin:

The Good News:

Metformin is now available generically, which means the drug is dirt cheap. Sadly, our confidence in the FDA’s ability to oversee the quality of foreign-made generic drugs has been shaken. The good news is that patients can monitor their blood sugar levels to see if the drug is working. If not, it may be possible to request the pharmacy try a different manufacturer.

Because metformin has been around for such a long time and is the number one most prescribed diabetes drug in the world, physicians have a very good understanding of this benefits and risks of this medicine. Unlike some of the newer medicines, there should be no surprises with metformin for diabetes.

Anticancer & Anti-Aging Bonus:

An unexpected bonus: the drug appears to have powerful anticancer activity. It seems to inhibit breast, colorectal, liver, lung, pancreatic, thyroid and prostate cancers (Annals of Translational Medicine, June, 2014). There is also some preliminary data to suggest that metformin protects against aging and may prolong life (American Journal of Obstetrics and Gynecology, June, 2017).

The Bad News:

The most common complication of metformin for diabetes is digestive distress. The number one complaint seems to be diarrhea. Other gastrointestinal symptoms include stomach ache, nausea, vomiting, loss of appetite, metallic taste, indigestion, gas and flatulence.

There are a lot of people who just cannot tolerate it for this reason. Here are a few stories from visitors:

Orlean in Georgia had horrible heartburn:

“I went on Metformin when my A1C went up to 6.2. There were no sign of me being a diabetic. I had no symptoms that there was anything going on.

“After 3 months on 500 mg three times per day, my A1C dropped to 5.9. My doctor checked my kidneys; then changed me to 500 MG twice per day.

“At first I was nauseated and had stomach cramps. That subsided. Then a few days later I started having diarrhea really bad. After the diarrhea came the heartburn which I think is the worst complication so far. Even without eating I get the heartburn.

“I go back in July to have my kidneys and my A1C checked, and I am hoping that my A1C is lower than 5.9. I need to get off this medication to start feeling like myself again. I like the fact that it seems to help with all the different cancers, because that runs rampant in my family.

“I wish everyone good luck with or without this medication. I only wish that I could find something that would help my heartburn. Nothing seems to help.”

Steve in Chicago reported similar problems:

“I was diagnosed with type 2 diabetes about four years ago. My blood sugar was 320. Naturally, my doctor put me on metformin (low dose, 500mg). After a few days I was having terrible stomach problems: mainly nausea and bad diarrhea. The drug made me feel deathly ill. These were the worst side effects I have ever had from a medicine, and I have been on many (blood pressure, depression, anxiety, etc).

“I went off it after a week and my problems disappeared after 3 or 4 days. I have since controlled my diabetes with diet (low carb) and exercise. Last A1C was 5.6. More power to you if you can take this stuff.”

Richard in Dallas, TX, tells about kidney problems:

“Metformin can also cause kidney failure. My late wife was taking metformin for several years. Then her doctor upped her dosage. About three months later she was in the hospital for kidney failure. After 2 dialysis treatments her kidneys returned to normal. BUT her kidney doctor said the cause of her kidney failure was metformin, and she could NEVER take the drug again.”

People with poor kidney function or diagnosed kidney disease should not take metformin for diabetes unless there are extenuating circumstances. Everyone on this medication should be monitored at least once a year for kidney function. Patients with congestive heart failure may also have problems taking metformin for diabetes.

You can read more about Metformin (Glucophage) Side Effects & Complications at this link. There are 140 comments from other visitors at this page.

Other Metformin Side Effects:

  • Headache
  • Rash
  • Fatigue, weakness
  • Anemia
  • Liver damage
  • Lactic acidosis

Lactic Acidosis and Metformin:

This is a very serious complication of this diabetes drug. Symptoms to be alert for include stomach pain, nausea, irregular heart rate, anxiety, hypotension (low blood pressure), rapid heart rate. Such symptoms require immediate medical attention!

We recognize that the side effects of this drug sound a bit daunting. Even so, most people tolerate it quite well.

One final word of caution: make sure vitamin B12 levels are monitored closely. This becomes especially true for anyone also taking a PPI-type acid-suppressing drug like esomeprazole (Nexium), lansoprazole (Prevacid) or omeprazole (Prilosec) That combination is a double whammy and could cause a severe B12 deficiency.

Learn more about Managing Diabetes:

We have prepared a Guide to Managing Diabetes with more information about metformin for diabetes. We also offer insights into other medications used to help control blood sugar. You will find nondrug options as well.

Anyone who would like a copy, please send $3 in check or money order with a long (no. 10) stamped (70 cents), self-addressed envelope:

  • Graedons’ People’s Pharmacy, No. DM-11
  • P. O. Box 52027
  • Durham, NC 27717-2027.

The Managing Diabetes guide can also be downloaded for $2 from the this link

Share your own metformin for diabetes story below in the comment section.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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