Pernicious Anaemia Society

Stopping treatment?

Was diagnosed with a B12 deficiency a little over 2 years ago with blood levels at 110. I was then prescribed daily sub linguals (1000mg/day). Most recently my levels were at 640.

GP now wants me to stop all supplementation for 90 days, and wants to retest. He says my initial levels were only mildly off and now that I am in a normal range he doubts continued treatment is necessary.

I am confused and a little worried that I will end up feeling like I did before. Not sure what to do. Is this safe?

13 Replies

It is pretty standard to stop supplementation for at least 3 months before checking B12 levels as supplementation will skew results.

Having said that though

a) your levels don't strike me as being particularly high given the doses you are taken - well over 1 years supply a day.

About 1% of B12 can be absorbed passively outside the ileum so assuming that you have a problem in the ileum you could still be absorbing over 3x the daily amount - which would have lead to your levels rising as they have over the time that you have been supplementing.

b) unless your doctor is absolutely sure that the original deficiency was caused by lack of B12 in your diet then the deficiency must have been the result of an absorption problem ... and unfortunately no amount of B12 is going to correct that, so as you say, take away the supplementation and you become B12 deficient again. It probably wouldn't be the full 3 months but ...

If your doctor has tested for PA and ruled that out as a cause then they need to be aware that

c) tests for PA are not very reliable - less than 50% so a result that says you don't have PA definitely doesn't rule out PA

d) PA is far from the only possible cause of malabsorption

Other possibilities are

- gastric surgery affecting ileum

- genetic abnormalities affecting ileum

- lowered levels of acidity in the stomach as you get older

- drug interactions - including many drugs used to treat early indicators of a B12 problem/symptoms of deficiency ... as well as drugs used to treat other conditions - eg metformin used to treat type2 diabetes.

The serum B12 test is not the best guide in the world as to whether there is a B12 deficiency or not - partly because it looks at all B12 and partly because it doesn't indicate what is actually happening at the cellular level. Active B12 is a bit more precise but still isn't conclusive

If you are in the UK then the recommendations are to treat on the basis of symptoms rather than test results in recognition of this problem

following may be of use (summary)

It might be worth suggesting a compromise to doctor - you will stop taking supplements but monitor if the symptoms return .... and if they do then doctor will take that as evidence that there is an underlying absorption problem and continue treatment = though depends on if the doctor is reasonable and takes any notice of the guidance (though if they do then might not be necessary).

Generally B12 isn't a controlled substance - only restrictions on it tend to be around injectible forms - so even if you can't get it through doctor you will be able to source the tablets elsewhere - the proviso being that you have the funds to cover the cost - although B12 isn't the most expensive drug in the world some of the high-dose tablets can be a little on the pricey side.

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Just looked at your profile and note you list asthma and ventolin - which does seem to be one of the drugs that can interact with B12 and interfere with absorption

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Thank you for your response! I don't think that diet could possibly be the cause of my initial deficiency; I eat plenty of meat/dairy and have never been a vegetarian or vegan. I can't imagine the Ventolin caused it either, I rarely need it and was diagnosed with asthma after being diagnosed with the deficiency.

I have never been tested for PA.

I started to become ill in 2004. I was very tired and dizzy a lot, had digestive issues while in university. I went to our student clinic a few times, but nothing turned up. I didn't see a doctor again until two years ago.

Over the last decade, I got progressively worse - just always assumed it was colds/allergies/long hours at work. Started having difficulties with my hands, and assumed it was repetive stress. Was in a perpetual fog, but also had trouble holding down a job and was living in a bad situation so assumed it was just stress.

Eventually, I got an industrial job and we had a paramedic on site who noticed that I wasn't exactly well and insisted I see a doctor. And here we are now.

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I wondered when the asthma cropped up - lots of people with B12 have problems with breathing so it might have been related to that - though also true that it could be totally unconnected.

Really hope that you manage to get through to the GP.


It is completely unacceptable for your doctor to withdraw treatment and your quality of life and ability to make progress is at risk.

Your original levels WERE low and the breathing difficulties could very well have been a neurological symptom of deficiency but the other symptoms you describe are neurological and should be treated urgently with injections as the guidelines already given. Your GP made no attempt to find out why you had become deficient and merely put you on (I assume) cyanocobalamin tablets, which is not the most effective way of treating. GPs generally don't understand the catastrophic effects of low B12. My family fought to eventually obtain monthly injections for our relative, who was misdiagnosed with ME, etc for years. We wrote setting out medical history, and followed up with the latest BMJ research and BCSH guidelines. It is as well to put things in black and white as I'm told that their biggest fear is being sued. These links might help in collecting information for the treatment you need.

(Templates for writing and an excellent film on this site)

The above UK research document is supported by many research papers and is peer reviewed. It also tells your GP that, once b12 treatment is started, the test results don't mean anything and blood levels are not reflective of how effective the treatment is but the clinical condition of the patient is.

Points from the Cmim/BMJ document Summary, if GP won't read full document:

"* Vitamin B12 deficiency is a common but serious condition

* Clinical presentation may not be obvious thus leading to complex issues around diagnosis and treatment.

* There is no ideal test to define deficiency and therefore the clinical condition of the patient is of utmost importance."

* There is evidence that new techniques, such as measurement of holotranscobalamin and methylmalonic acid levels seem useful in more accurately defining deficiency.

* If clinical features suggest deficiency, then it is important to treat patients to avoid neurological impairment even if there may be discordance between test results and clinical features.

Severe deficiency shows evidence of bone marrow suppression, clear evidence of neurological features and risk of cardiomyopathy.

It is important to recognise that clinical features of deficiency can manifest without anaemia and also without low serum vitamin B12 levels. In these cases, treatment should still be given without delay."


Yeah everything she said. I only have one thing to add. If you get the sublingual B12 get the Bariatric formula. It's specifically designed for absorbtion problems in people who do not absorb in the digestive tract.


The more I read the more I realise that GPs are complete numbties (I have better nouns/verbs...) with regard to chronic illness - mildly off at 110? really?

isn't the lower level in Japan 500? For the sake of 60p an injection after all....

Yet why have Vital mineral training at all? Oh GPs don't - no free lunch there...

I'd tell my GP I'm a vegetarian or vegan - if they need a reason - hey it's just treated as a pain killer in the USA!

low B12 in Thyroid 40%

I have a film from the 1930s, & wondered why it seems to be a secret that they knew this 80+ years ago???


Totally agree Sparerib. There are research papers, books, guidelines and now a film out - Sally Pacholok and her husband ("Could it be B12"), worked in a US city emergency department and saw hundreds of misdiagnosed patients dying or becoming disabled for life, and yet nobody listened... There is the PA Society and Martyn Hooper's books. Prof David Smith, who has done research on B12 and dementia (recently on radio's 'Inside Health') saying something should be done....

There are people in psychiatric treatment wrongly diagnosed with psychosis, Schitzophrenia and dementia, etc.

My sister's memory has not fully returned because of the delay in treating. Even after admitting it could be B12 def. they tried to fob her off with Cyanocobalamin tablets, which are not easily absorbed.


PS Thanks for the interesting link - four in our family have hypothyroid disease..


B12 isn't treated as a pain killer in the USA. However saying is now the biggest fad in the high priced Spas. They're saying it's a great weight loss aid. They really need to do their homework cause a true weight loss aid is B12 def. It can cause anorexic like symptoms. But they have driven the price up to a ridiculous amount per bottle. The Spas are charging up to $300 a shot.


My gp did the same thing. I never got my treatment reinstated. I now have to self inject.

I hope things work out OK for you.

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Thanks all. This is all very new to me, and rather puzzling. I am never quite sure what to make of it. Growing up, I was always very strongly discouraged from seeking medical attention, and I always feel like I am wasting time and should just toughen up.

So I generally don't bother. I am not sure that's so wrong, since I am so deeply skeptical of medics.

I mean, I missed most of my last year of university because I couldn't walk to class without violently coughing until my lips turned blue, there was incontinence and I generally collapsed. Never occurred to me to see a doctor - and when I did? After approximately a decade of that, was told I was a hypochondriac by many medics who didn't even examine me.

So what's the point?

It doesn't help that I am practically incapable of being honest about how I feel - I have been gasping for breath and unable to feel my arm, but still smiling and insisting I am "OK."

When first diagnosed with a B12 deficiency, it was a different GP (has been every time - only now have I been assigned a family doctor). She offered me injections, and I declined. Didn't understand what this was and couldn't fathom getting enough time off work to be at the doctors office so much.

Maybe after this next appointment, I won't need to go back and can manage on my own.


The injections are what's going to get you back on the road to recovery, please don't dismiss them. I had problems similar to yours for about 5 years and was back and forward to my GP who insisted that I needed Prozac. Then one year ago a Dr said to me, please tell me you have started your injections, figure down to 98. I had no idea what she was talking about. I am now receiving injections every month and am just about managing, figures up to about 423 a month ago. This condition is a marathon not a sprint and I so wish you well with your journey.


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