Nerve Damage Caused By Metformin?!

By MAYS Latest Reply 2017-09-03 08:25:06 -0500
Started 2012-06-24 19:45:36 -0500

Metformin Side Effects

Metformin is one of the most commonly used medications to treat type 2 diabetes.

It’s inexpensive, available in generic form and quite effective for lowering blood sugar levels.

Some preliminary animal studies also show that taking metformin has additional benefits such as reducing the risk of certain types of cancer - and it may even prolong life.

But there are side effects of metformin that many doctors don’t talk about with patients.

Taking metformin can cause permanent nerve damage.

(B12 and Metformin Nerve Damage)

How does a drug like Metformin that has so many benefits cause such a severe side effect as nerve damage?

Three out of 10 people who take metformin long-term develop a deficiency of vitamin B12. It can take 10 or 15 years to develop symptoms of B12 deficiency since the liver stores B12 - and it can take that long to deplete those stores.

B12 deficiency causes damage to nerves that may be irreversible.

Unfortunately, B12 nerve damage may be mistaken for diabetic neuropathy - and may not be recognized as a metformin side-effect. Thus, it may go untreated and become permanent.

B12 neuropathy usually starts with numbness and tingling in the feet and hands, but this side effect gradually progresses to muscle weakness and balance problems.

The symptoms closely mimic those of multiple sclerosis.

If vitamin B12 deficiency goes untreated, a person with this deficiency can lose the ability to walk. Fortunately, replacing the lost vitamin B12 can reverse B12 nerve damage – but only if it’s caught early.

How Can You Prevent B12 Nerve Damage if You Take Metformin?

If you’re taking metformin, ask your doctor to check a vitamin B12 level through a blood test at least once a year. If your levels are low, you can get B12 injections monthly to bring them back up and reduce your risk of B12 neuropathy and nerve damage.


45 replies

Anonymous 2017-09-03 08:25:06 -0500 Report

I was diagnosed with type 2 diabetes about seven years ago and my doctor put me on metformin. The past couple of years I have noticed that I get numbness and a burning tingling in my toes on both feet. I mentioned it to my doctor and he said it was diabetic neuropathy.

I did a search on the internet a couple of weeks ago and I found an article that said metformin depletes vitamin B in your body. I bought some Stress Tablets with Vitamin B12 complex in it and took two tablets and with two hours the pain, tingling and burning in my feet subsided. I have found that I need to take a couple of B12 stress tabs every couple of weeks to keep the symptoms in my feet under control.

When I was diagnosed seven years ago I weighed 244 pounds. I forced myself to start eating one good meal a day and in less than a year I lost 60 pounds. By losing weight my blood sugar levels have dropped, to the low 80's when I weighed 60 more pounds my blood sugar averaged around 130 in the morning (fasting). I just tried an experiment this week. My feet started having symptoms of tingling, burning and and numbness again in my toes, so I decided to stop taking metformin. Too my surprise, all of the tingling burning and numbness in my toes went away completely after two or three days and blood sugar levels dropped. Here is my blood sugar levels for the last four days after stopping metformin. Day 1 (83), Day 2 (80), Day 3 (90), Day 4 (82). My next doctor appointment is the third week of October. I am going to keep testing my blood sugar levels daily to show my doctor the results and I am going to stop taking metformin unless my blood sugars spike and go higher.

I think losing weight has helped reduce my blood sugar levels enough that I don't need metformin especially since after stopping it four days ago the problem with numbness, tingling and burning in my toes has completely gone. I am starting to think metformin is poison. Gonna run all of this by my doctor when I see her in October.

hunney000 2016-07-06 12:06:27 -0500 Report

I have a friend who's husband was having severe problems with his feet. The doctor that treats his Diabetes referred him to a Neurologist. He did a nerve conduction test that proved he had severe Neuropathy. He went back to the Dr. that treats his Diabetes and the Dr. recommended that he take B12, 150.00/month. The Dr. told him the Neuropathy was a result of Diabetes. Although he had been taking Metformin for about 2 years and never had the problem prior to taking Metformin. I feel like the Dr. must have known about the problem with Metformin, but failed to tell him. I sent an article to them about Metformin causing Neuropathy because my husband had a bad experience with the drug. My friend and her husband were perplexed because since he found out he had Type 2 Diabetes and he began taking meds, his A1C had decreased, yet his feet became infected.

hunney000 2016-06-30 07:58:30 -0500 Report

My husband was taking Metformin for about 2 years. He started having severe pain and weakness in his hands. He thought he had Arthiritis. He went to an Orthopedic Dr. The Dr. told him he did could not find a problem. The pain continued to become worse, to the point of his hands becoming useless. For some reason he suspected Metformin. He stopped taking it and eventually the pain got better. He wen to the Dr. that prescribed the Metformin and told him. He told my husband that he had never heard of that and he refused to change his medicine. Now he does not take medicine, but he can use his hands. He still does not have full use of his hands, but they are much better.

WASHED OUT 2016-06-30 08:15:07 -0500 Report

It is a B12 deficiency that can cause nerve damage over a long period of time something that many of us are aware of and take supplements or shots to replenish. A simple blood workup will show if there is a deficiency.

hunney000 2016-06-30 09:22:36 -0500 Report

Thank you, I must convince him to have a test. But I fear much irreversible damage has been done. Still we are thankful that it is not as painful and he has regained use.

WASHED OUT 2016-06-30 09:35:02 -0500 Report

I know pain well I have RA and permanent nerve damage in feet and legs. I no longer even have reflexes in my feet and legs due to back injury and diabetes.

WASHED OUT 2016-06-30 10:32:42 -0500 Report

I only pass along what I have learned from my own experiences and the research that I have done. It gives people the right places to look for answers and what has worked to help many in our group here find diet glucose control. Might I suggest you try looking at Dr Richard Bernstein's Diabetes University on youtube and I highly recommend his book" Diabetes Solution ". You may be able to find in your local Library, he is a Diabetes specialists who also has diabetes. He has led the way and pioneered control and understanding how to achieve normal glucose levels. Here is a link to his youtube site.

roxanne bohnnow
roxanne bohnnow 2014-12-01 14:30:33 -0600 Report

After reading this I went out and bought a huge bottle of B12 at the local pharmacy. I am hoping that this will do the trick for me, but I am still willing to get the B12 shot if needed. I have been getting some real pain in my right upper leg and my right hand keeps going numb and falling asleep for no reason at all.

granddad77 2015-04-14 10:35:50 -0500 Report

Be very careful with metformin, a bottle of b12 may not work according to researchers.

Apparently the path in which Metformin destroys the nerve fibers may not be helped with b12. I highly suggest you consider grapefruit Juice as oppose to metformin according to UCLA.

See here

GabbyPA 2015-04-14 10:57:29 -0500 Report

Sadly, many diabetics are on Lisinorpil and you cannot consume grapefruit in any form while taking that drug. Grapefruit interacts with many medications so I would suggest talking to your pharmacist before doing so.

onalaska 2015-10-26 19:30:23 -0500 Report

this is extremely untrue I take lisinipral and asked my pharmacist and he said grapefruit is just fine to take with it no harm no interaction at all

GabbyPA 2015-10-27 09:33:13 -0500 Report

My pharmacist is the one who told me about it. I asked my doctor if I could consume grapefruit in the morning because I take my lisinopril at night, and he said binds to the med. So I will just skip it and not take the chance.

onafixedincome 2016-07-02 11:56:20 -0500 Report

Gabby, there's no interaction listed for lisinopril, although other drugs used for hypertension do indeed conflict. Hope that helps!

Trudie Ann
Trudie Ann 2014-03-17 02:14:02 -0500 Report

WOW!!! I knew I have nerve damage from more than one source but I never imagined Metformine could also be a cause. I only knew that it was from my disc damage, and shingles damage. Thank you soooo very much for this post.

Grandmama16 2014-03-16 15:18:13 -0500 Report

I'd say, be the squeaky wheel. Maybe you could contact your Ins. My Ins has required my Dr to pres Lipitor for Cholesterol and I don't want to so I halved the dose to compromise but actually I could just not take it. With Medicare, to get my testing supplies, I have to prove I'm testing twice a day so I copy my little book pages and give them to the pharmacy. Seems silly. Take care, M.A.

GabbyPA 2014-03-16 11:41:53 -0500 Report

I have asked for a b12 test from my doctor to find out if I have that, but they say no, that it's just for the elderly who don't have a good diet. Really? What do I have to do to get my doctor to check the things I am concerned about?

Grandmama16 2014-03-15 14:24:22 -0500 Report

I have the symptoms of deficiency but haven't been taking .metformin that long.. I try to remember to take a liquid B12 I have and also other vitamins. Dr has suggested in the past that I come in for the shots, due to my fatigue. Is it good to do that and get a jump on the whole side effect thing? I guess it couldn't hurt. It's just remembering to do so.
My A1c was 6.6 last time so that's good.

ICDA250 2014-03-15 09:01:32 -0500 Report

I had heard of the B-12 deficiency and Metformin link and after a vitamin blood work profile, I was given regular B-12 injections before having my Metformin discontinued. Now I wonder if the cramps and other problems with my fingers are not solely related to the dislocations and fractures of my finger and could also be related to nerve damage. I was on Metformin without any vitamin deficiency blood work for more than 15 years.

Grandmama16 2013-11-14 13:50:24 -0600 Report

Wow…another thing to worry about. Thankfully my Dr. Listens to things like B12 testing. I could go in for a shot once a month but right now I'm taking a liquid B12. I do have the symptoms described and am taking Neurontin but it's side effect is sleepiness so I take 200 mgs in the afternoon which I've done slowly and 300 mgs at night which was a separate pres. Is that too much? I'm supposed to increase it to 300 in the afternoon. So far, the itching I had on ankles,no rash, and feet for years has subsided, and shooting pains in hands but still have numbness. I had a nerve test done but no results yet. I'm supposed to get blood test done in a month for A1C. I was only diagnosed last year and just thought symptoms were from fibromyalgia. I take 1500 mgs Metformin but had to work up to it slowly. Thanks for the info.

GabbyPA 2012-06-25 21:26:56 -0500 Report

I knew it could deplete the B-12, but I had no idea that it was related to our nerve damage. Dang. It is so hard to figure these things out and choose between the benefits and the risks.

I asked my doctor to do a B test on me, but he won't because he reserves that for older patients who tend to not eat a balanced diet. Sigh....why they won't listen to us is so bothersome.

hunney000 2016-06-30 08:02:06 -0500 Report

My husband told his Dr. that Metformin was making his hands useless. The Dr. told him that he had never heard of that and that was not the cause to keep taking it. It was the cause.

Trudie Ann
Trudie Ann 2014-03-17 02:07:01 -0500 Report

I didn't know about b12 test. I had heard it causes b12 defficiency so I take a supplement. I will see if I can get the test too. I went to my doctor and asked about getting a shingles shot. He said I could get one but at my age Ins, wont pay, that I would either have to wait till my next birthday or pay full price, Guess what! Two months later I got the shingles. I sure wish I had payed full price or that insurance companies could be a little more lax. for diabetics.

MAYS 2012-06-25 22:38:54 -0500 Report

Diabetes seems to be so complicated at times.
I agree with you on the subject of doctors listening to patients, it seems that we speak a language that they refuse to understand when we suggest something or question their actions or intentions.

Squirt48chester 2015-04-05 18:25:48 -0500 Report

Hello there everyone! I just joined this site. Little or Maybe Lot of info on me . Diagnosed Diabetic about 1 year ago right b4 my oldest brother died from cancer. Was diagnosed while in hospital & they started me on 500 mg Metformin 2 x day, Every since I have been Constantly in & out of the hospital to the point I now Know all the Nurses & Aides & Every One else that works on the 3rd floor of the hospital & they know me! Well just Released Today after Another 5 day stint this time Due to same thing as usual ( Nausea , Diarreah, Severe Weight Loss in Short amount of Days & So On) !! The Internal Medicine Dr. went back over my chart for the last year & GUESS WHAT?? Yup you got it ALL DUE TO METFORMIN!!! So now I gotta be PATIENT & let it get out of my system. He put me on Glyburide & I have to go to my Regular Dr. A lot more often till everything is worked out But hey feel Better & Stay Out of Hospital & Get Back to a Normal Life I can be Patient even if it drives me nuts!! It's nice when u have a Dr who WILL ACTUALLY LISTEN TO YOU & REALLY HELP YOU. I TRUELY BELIEVE I WAS MEANT TO BE THERE ON EASTER FOR MY OWN LITTLE MIRACLE!! THANK YOU GOD!! Sorry had to get that out to somebody who understands this Disease.
GOD BLESS YOU ALL. Sorry for bending YALLS ears.

jayabee52 2015-04-05 18:54:33 -0500 Report

Howdy Chester
Glad to hear the Dr finally heard you and changed your meds

Don't stop advocating for yourself, especially if this new medication is giving you problems.

Praying you can stay out of the hospital!


Trudie Ann
Trudie Ann 2014-03-17 02:09:12 -0500 Report

I agree some doctors act like since you've never been to medical school that you don't know what your talking about.

ICDA250 2014-03-15 10:32:02 -0500 Report

It seems like some physicians are unable to employ a "global perspective" when working with patients and think outside of the box. Some physicians only focus on conditions or problems they feel most comfortable with treating such as limiting treatment to a sub-specialty… they can miss the forest because of the distraction of the trees. The psychological constructs of selection and attention cause them to dismiss valid concerns of patients.