Diabetes medication Metformin and its affect on B12 levels

[clivealive]

I've had PA for 43 years and am on four weekly Cytamen 1000mcg b12 injections.

In May 2015 I was diagnosed with Type 2 diabetes, prescribed 4 x Metformin 500mg daily.

Will this medication affect my B12 levels?

[Galixie]

Yes. Metformin is known to lower B12 levels. That's a side effect that you should probably discuss with your doctor because you may end up needing more frequent B12 injections.

It is a well known side effect. If your doctor isn't aware of it before you mention it, you'll be doing everyone a service by making your doctor better informed.

[clivealive Forum Support in reply to Galixie]

Thank you Galixe,

Can you please tell me where I can get printable, authoritative evidence of the "well known" adverse affects of Metformin on my B12 levels that I can present to my doctor?

I would be most grateful for your help.

[Galixie in reply to clivealive]

I googled "metformin side effects" and here are the first few sites that came up:

drugs.com/sfx/metformin-sid...

You have scroll down a ways to get to this line:

"Hematologic

Very rare (less than 0.01%): Subnormal vitamin B12 levels[Ref]"

But if you click on the "[Ref]" at the end of the line on the webpage it takes you directly to the reference material listings and that would be another source of information to look up.

webmd.com/drugs/2/drug-1128...

This one lists "Inadequate Vitamin B12" as one of the common sides effects.

medscape.com/viewarticle/71...

"However, a common, potentially damaging, and well-documented complication of metformin—vitamin B12 malabsorption—is poorly recognized and not screened for or treated prophylactically by the majority of physicians who prescribe metformin."

My search was very rudimentary, but hopefully it will start you off in the right direction. I found that last webpage by googling "metformin side effects b12 deficiency"

[clivealive Forum Support in reply to Galixie]

Thanks again Galixe,

I found the Medscape article very informative together with some of the comments made thereon.

Hopefully it is referring to malabsorption via normal digestion but maybe the frequency of my B12 injections will need to be "looked at".

As I had two thirds of my stomach removed when I was 17 years old in 1959 "normal digestion" has not been possible for 55 years.

[Gambit62 Administrator]

The evidence on metformin's interaction with B12 is a bit mixed. It is known to inhibit absorption - though as you have an absorption problem anyway that may be slightly irrelevant.

At least one study I've read implied that metformin may actually increase the efficiency with which B12 is processed - sorry but I don't have a reference to the relevant studies to hand.

Sorry - I know that isn't much help. In theory if it increases the efficiency with which you are processing B12 it might actually be beneficial but ...

[clivealive Forum Support in reply to Gambit62]

That's very interesting - thank you Gambit62

My PA was as a result of two thirds removal stomach surgery in 1959 when I was 17 years old so normal absorption of B12 through the gut became virtually impossible. Sadly this was not recognized and diagnosed until the early 70s. I can only hope that the "theory" that Metformin might actually help absorption is accurate......

[Gambit62 Administrator in reply to clivealive]

if I get some time over the next few days I'll try and see if I can refind the details.

Sorry that it took so long for your B12 problems to be recognised - it is a bit worrying that medics seem so unaware of the consequences of stomach surgery on B12 - know someone else who was in a similar position and his problem was only diagnosed when he blacked out in the street and had to be hospitalised. Gets even worse when you consider the number of people who are having gastric band surgery for obesity ... like lemmings to the edge of the cliff.

Type 2 diabetes is a bit of a pain - we have diabetes running in my mothers side of the family - but it isn't a type 2 form though it occurs late in life - my brother started to suffer a few years ago and was initially put on metformin but it wasn't working for him - fortunately my mother was involved in a study that was trying to identify the specific gene responsible for that form of diabetes so he was able to argue with his doctor that it wasn't type 2 and was moved to a different medication which did work. Even the things that look simple can often be much more complicated but it can be a battle to get GPs to recognise that. I was tested and didn't have the gene though I was at that point where if I did have it I probably would have shown signs of diabetes when I was tested ... so have a special interest in diabetes because I grew up with it as an ever present factor in the family. It could make life a bit more complicated as there is a huge overlap on some symptoms of B12 and diabetes so really hope that you have your B12 medication properly sorted out.

[clivealive Forum Support in reply to Gambit62]

Sorry to read about your family problems with diabetes, my father had Type 2 and my sister Type 1.

The connection between stomach surgery and PA was not recognized until the 60s or 70s and thirty years prior to that the only remedy available was to eat raw liver 3 times a day.

My GP who "discovered" my PA (via Schillings test in 1972) jokingly gave me the following options

Do you want the good news or the bad?

Give me the bad

You're going to die - and within the next 3 years.

What's the good news?

You're not going to die if you have these injections every four weeks for the rest of your life.

Doctor Wool is now a Dame of the Order of the Bath - and I'm still alive at the age of 74 so she was right and the injections are working...

I wish you and you family well - which reminds me I need to get on to my daughters to be aware of their potential susceptibility for diabetes

Thanks for your time and patience.

Clive(still)alive

[Polaris]

umm.edu/health/medical/altm...

[clivealive Forum Support in reply to Polaris]

Ah - Got ya. Thanks again Polaris.

[clivealive Forum Support]

Hmm. No mention of Metformin then! Thanks for that link Polaris.

[Gambit62 Administrator in reply to clivealive]

actually if you click under anti-diabetes metformin comes up.

the link gives you the classes and then you have to click on them to see the specific drugs.