Treatment beyond the loading dose of b12 - Pernicious Anaemi...

Pernicious Anaemia Society

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Treatment beyond the loading dose of b12


I've had the loading dose of 6 injections and noticed improvement along with great tiredness on the day after the jab. As I have neuro symptoms I asked for further injections every other day as laid down by the NICE Guidance. GP was shocked at the thought of so much b12 and I had to show her the guidance in writing. Then she reluctantly agreed to give me two more week's worth. Last week I should have had the last three injections but the nurse couldn't fit me in!! so I only had one I.M. Improvement has slowed down now but not stopped.

GP has 'taken advice' from a haematologist who says in my case, as I have a serum b12 in normal range, it is unlikely that there will be any further improvements after 4 week's treatment.

Is it the case that there are known recovery rates for different serum b12 starting points.

Any views would be welcomed.

15 Replies

I've not heard of any statistics of recovery rate. I was told by a neurologist most healing done in the first 6 months. I'm glad that not correct for everyone as I'm still making improvements 10 months in.

Surly if they are helping you maintenence of every 2 months should be given.

No, there is no apparent connection between recovery rates at initial B12 values.

The haematologist is talking rubbish. Because he/she is blinkered. They believe that the haematological consequences of a deficiency are all that matters. And those should, indeed, clear up after three to four weeks. They have absolutely no idea at all about the neurological consequences.

Ask to see a neurologist. You will abide by their opinion, but need your continued loading doses while you wait.

Note: minor edit by admin

Yes, as fbirder said, GPs don't seem to understand the difference between the haematological and the neurological requirements. I just ran into this with my Doctor yesterday and thankfully she has finally agreed to refer me to a Neurologist. The issue as I have understood it is to have the blood concentrations so high that you get it through the blood-brain barrier, etc, into the nervous system to try to halt and hopefully repair the demyelination. We also had another discussion about her not being able to prescribe outside the guidelines and it was interesting to find out that those guidelines are set by the Pharmaceutical manufacturer - I thought it was a Medical Board (or whatever it's called) decision. I would like to have the NICE Guidelines if you/someone could give me a link. Thanks.

fbirder in reply to BirdlessBox

B12 crosses the blood-brain barrier via the same mechanism whereby it gets into all cells so that shouldn't be a problem. The main problem with neurological as opposed to haematological recovery is one of timescale.

Blood cells normally regenerate after three months and the body has processes to speed this up (because loss of blood cells isn't a rare occurrence). So it doesn't take long at all for the blood to return to normal.

But nerve cells (and the cells that make up their myelin sheath) regenerate very, very slowly. I severed one of the nerves in a finger in my 20s and it took 10 years before feeling was back to normal. So any damage caused by a B12 deficiency will take a long time to repair itself.

Guidelines for dosing frequency aren't set by the manufacturer. Otherwise they would want to maximise sales by making it as often as possible. The NICE guidelines are here - Various people have spent a lot of effort trying to pin down the scientific basis for those guidelines, and why they have been changed in the past. With no joy at all. It seems that they were plucked from the air by an accountant.

NICE say they were based on evidence from the BCSH and recommendations in the BNF.

The BCSH say their recommendations are those of the BNF.

The BNF say that their recommendations are based on those of NICE and the BCSH.

BirdlessBox in reply to fbirder

Thanks. It frightens me that they are so casual about treatment when the neurological damage is so difficult to repair. I wonder if the pharmaceutical companies aren't trying to sell more because their profit margin is so much higher on the other drugs used when our condition is misdiagnosed. I was staggered at what the lady in the U.S. was having to pay for B12 though. I'm in NZ.

fbirder in reply to BirdlessBox

This is a common belief - that 'Big Pharma' have total control over what doctors prescribe. It is totally wrong.

One of the most common claims is that Big Pharma bribe doctors to prescribe antidepressants rather than B12 injections. But it just doesn't add up.

Here in the UK just about every antidepressant you might get prescribed isn't made by Big Pharma. Their patents have expired and you will be prescribed a generic version, manufactured by 'Teeny-Tiny Pharma'. And it will cost the NHS very little to buy those pills.

To buy 30 capsules of fluoxetine (generic Prozac) from Almus Pharmaceuticals (just one of 19 different companies that sell it, all for the same price) costs the NHS just £0.93 Almus Pharmaceuticals made a profit of £260,000 in 2018. There are about 7000 GP practices in the UK.

That means, if Almus Pharmaceuticals were to bribe every GP practice in the land it could afford to give each one £37.

How many GPs would risk losing their license for a part-share on £37? Would small pharma risk losing their business just to sell more pills at 3p each?

Doctors hand out antidepressants rather than give B12 injections because they do not understand B12 deficiency. Not because it allows them to buy a yacht in the south of France.

BirdlessBox in reply to fbirder

My Doctor said directly to me that she has to follow the prescribing recommendations the manufacturers put on their products. I suppose if the people who make them say this is how they are to be used then that is what is accepted by the medical management, anything else would be illogical. We seem to have been presuming that the prescription practices are the responsibility of the medical system when, perhaps, it is not. Our efforts to get change may be misplaced - it might be more productive to tackle the manufacturers to get them to broaden the prescribing recommendations than keep on hoping the doctors will deviate from them.

fbirder in reply to BirdlessBox

No. It is not the manufacturers who decide the prescribing recommendations.


"had another discussion about her not being able to prescribe outside the guidelines"

GPs are allowed to prescribe outside the guidelines if it is their professional judgement that it is appropriate for the patient to do so.

I think the issue is that most GPs choose not to because they don't want to risk criticism.

See Point 69iii in next link about prescribing unlicensed medicine.

Yes, people hate risking being responsible if anything were to go wrong. I am in New Zealand but that shouldn't make too much difference.

Thank you for replying. I am slowly beginning to understand the whole thing a bit better, so that I will be able to frame my arguments more logically.

My neurologist was really helpful and i am now on 6 weekly injections.


I'm still experiencing some improvement over 6 years after starting treatment and I had multiple neurological problems.

A few links that may be of interest. ..apologies if I've already posted these on one of your older threads.

UK B12 documents

BSH Cobalamin and Folate Guidelines

Flowchart from BSH Cobalamin and Folate Guidelines

Flowchart outlines process for diagnosing PA and Antibody Negative PA in UK

BMJ B12 article

Emphasises need to treat patients who are symptomatic even if their B12 level is within range.


BNF guidance on treating b12 deficiency changed recently.


BNF Children


B12 books I found useful

"What You Need to Know About Pernicious Anaemia and B12 Deficiency" by Martyn Hooper

Martyn Hooper is the chair of PAS (Pernicious Anaemia Society). Book does not show updated BNF info.

"Living with Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper

Has several case studies.

"Could it Be B12?: An Epidemic of Misdiagnoses" by Sally Pacholok and JJ. Stuart (USA authors)

Very comprehensive with lots of case studies. There is also a paediatric version of this book "Could It Be B12? Paediatric Edition: What Every Parent Needs to Know".

PAS (Pernicious Anaemia Society)

Based in Wales, UK.


PAS tel no +44 (0)1656 769717 answerphone

PAS support groups in UK


Blog post about how PAS can support PAS members seeking PA diagnosis

PA tests

Intrinsic Factor Antibody (IFA) test

Parietal Cell Antibody (PCA) test

PCA is not recommended as a diagnostic test for PA in UK.

Both these tests can be unreliable.

It is still possible to have PA with a negative result in IFA or PCA test.

About 50% of people with PA test negative on IFA test.

About 10% of people with PA test negative on PCA test.

B12 Deficiency Info website

B12 Awareness (US website) holds support meetings near Durham, UK

Stichting B12 Tekort (Dutch website with English articles)

UK B12 Blogs

Martyn Hooper's blog about PA

B12 Deficiency Info blog

"As I have neuro symptoms I asked for further injections every other day ....GP was shocked at the thought of so much b12"

Did your GP explain why she found the idea so shocking; what did she think more B12 would do to you?

"Treatment with high dose vitamin B12 been shown to be safe for more than 50 years"

"Misconceptions about a B12 deficiency"

Are your GP and haematologist aware of the potentially severe consequences of under treatment?

I agree with fbirder that seeing a neurologist is a good idea.

I used to put referral requests into a brief, polite letter to GP along with evidence that supported request eg symptoms, test results, family/personal medical history, extracts from UK b12 documents etc.

GP does not have to agree to request though.

Be well prepared for any neuro appointment; sadly ignorance about b12 deficiency can exist among neurologists. I can vouch for that.

Neurological Consequences of B12 Deficiency

PAS news item


PAS article about SACD, sub acute combined degeneration of the spinal cord, access to PAS members only.


Blog post from Martyn Hooper's blog, mentions SACD

Unhappy with Treatment (UK info)?

Letters to GPs about B12 deficiency

Point 1 in this link is about under treatment of B12 deficiency with neuro symptoms. Link has letter templates to base own letters on.

CAB NHS Complaints

HDA patient care trust

UK charity that offers free second opinions on medical diagnoses and medical treatment.

I am not medically trained. More B12 info in pinned posts on this forum. I've written some very detailed replies on other threads recently. May be worth searching for them.

Thank you for your detailed reply. How many times do you inject now?


I don't talk in detail about my self treatment but I will say that I need a lot more B12 than in the UK guidelines and my symptoms start to return within a few days of an injection.

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