Pernicious Anaemia Society
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New to injections..what to expect?


I've just had my 5th injection in 5 days (I also had 3 weekly injections prior to this) and have had not improvement in my symptoms-namely faintness/dizziness.

Am I being impatient? Would anybody like to share their story of injections and neurological symptoms? I've only read of people receiving loading injections and feeling much better afterwards.

I am also in my fourth week of taking sublinguals (2500-5000mcg/day) and have added folate, multivitamins and potassium and magnesium to help my body. I've had a few small improvements in other areas- joint pain has eased, legs feel a little stronger (I had weak/numb legs), some stomach problems have cleared and I'm urinating much less frequently (I hadn't even realised that my frequent urination was a result of B12 deficiency).

Thank you for any reassurance!

18 Replies

Can only advise that you give it a bit of time. Many of us do in actual fact feel significantly worse just after loading. It has been suggested that it is the body responding to the high level of input of something which it has gone without for a while.

I had really bad breathlesness just afterwards, almost like i was having a panic attact and couldnt walk anywhere. But before loading i had never suffered this, just very shallow breathing. Gone now thankfully!

I self treat using patches and methyl drops which has helped quite a lot, as well as 3 monthly jab. Im now 9 months post diagnosis and have just been told i am celiac. Another complication to throw into the mix!

I dont know how true this is but i have heard that the healing works backwards ie last symptom in, first to go.


Lisahelen Thank you, I am perhaps being impatient. Also, I have never been officially dignosed - my serum B12 level was 243 and 3 doctors refused to treat me in spite of bringing info in, pleading I had to go alone and I think this makes me more anxious- in case I have got this all wrong. I diagnosed based on my symptoms, my blood test results (low B12, macrocytosis, high folate)..and all tests coming back clear


If the faintness and dizziness are down to the anaemic effects of B12 - which is quite possible given that you mention you had macrocytosis - then it is likely to take a while for everything to get 'back to normal'.

B12 is used to regulate the production of cells - including red blood cells - if there isn't enough B12 then the cells tend to get larger and more spherical - macrocytosis. This means they are not as efficient at transferring oxygen from your lungs to where-ever it is needed. Once you have enough B12 then the body should start producing normal red blood cells but it is going to take a while for your body to replace all of the red-blood cells that you currently have with new healthy blood-cells - red-blood cells have a life of about 120 days so that is a number of months.

This may help ... or it may just be more confusing - haven't watched it all the way through

The breathlessness isn't always or necessarily just down to anaemia - it can be a neurological effect of B12 on the autonomic system - with the body getting confusing signals about whether it needs more oxygen. This element of the problem might resolve quicker or faster than the anaemia.

Sounds as if you are noticing improvements in other areas - try to focus on these.

Many people report that it takes about 6 months before they start to notice a difference.


Hey, thank you. I tried to watch video but it won't let me. Do you remember the title-perhaps I could find it on YouTube?

I have wondered about the cause of faintness-understanding a symptom makes it a little less scary to deal with I think. My macrocytosis was mild (but enough for them to order a B12 test after the full blood count). I wonder if a few enlarged blood cells could cause perpetual faintess/lightheadedness. I suppose our bodies are delicately balanced.

I have wondered if nerve damage in the brain might also be causing the faintness-I guess that too would take time to correct.

I don't have breathlessness as such. I don't have a vast range of symptoms-the leg weakness and faintness are the only two which are really troublesome.

I had to self-diagnose and treat after doctors refused to accept B12 might be the problem because my levels were within range (243).


sorry about the link - I had problems with it getting it to run at first - and the link above isn't working for me either

wonder if this one will work any better - hope it does


Gambit62 - alas not! What is the title? I can take a look myself


edited to a play list whilst you were trying - see if that works - the first one is the one that talks about red blood cell production and anaemias


It took a long time for me to respond to shots. I had weekly injections, and it took about 7-9 months for feeling to really return (but it would go away before my next shot) and about 11 months for feeling to remain steadily between injections.

It took about 3-4 months before I really felt improvement at all, but it would not last. The shortness of breath, loss of appetite, irritability, numbness, etc would return within hours!

I had numbness all over, particularly extremities, and trouble walking and with fine motor skills.

Take heart, and keep doing the best you can. It may take a while, but that doesn't mean it's hopeless.


Did you really have weekly injections? If so then I don't understand what you mean by 'but it would (what would) go away before my bed shot'. I can see that you say later that 'it' would return within hours though if you were having daily injections for months.


Sorry- after a few months of shots my sensation started to improve about a day or two after each weekly shot, but improvement would not remain. The numbness would return within hours.

It took several months before improvement in sensation remained between injections.

I have never had daily shots.


Allyson1 9 months - Crikey! Glad you finally made it through to the end :)

I had to self-diagnose and treat as doctors refused point blank to even try a therapeutic trial because I was within range (B12 level was 243 and doctor said this was "absolutely fine")-because of this I'm perhaps a little anxious and paranoid that I may have misdiagnosed.

I'm on daily injections at the moment and also sublinguals - I'm hoping this will speed up my recovery but I guess it may still take months. My most troublesome symptom is faintness/dizziness. I know macrocytosis is a possible cause for this and wondering how long this would take to correct - I guess 120+ days (a cell's life)!!


Not sure it's the end get, I still have neuro symptoms, just milder:/.

Keep an eye on your potassium and magnesium, and take it one day at a time!


There can be no definitive time scale Booksellercate as we are all different as too the delay before diagnosis and the amount of "damage" that has occurred before treatment. Mark each individual improvement as an achievement and for the time being take one day at a time.

To read my P.A. Story click on my name at the top of the message


clivealive Thank you very much.

I am so desperate to start feeling better I am getting rather impatient.

I had to self-diagnose so I will not know if B12 is causing my problems until the treatment starts working. If I am wrong, I will have to possibly wait months to find out and may perhaps be at square one again-but let's hope not!


I've re-read through your posts Booksellercate but can't see how long you have been suffering the symptoms of what you "think" is either B12 deficiency or P.A..

I had two thirds of my stomach removed as a result of a perforated peptic ulcer at the age of 17 in 1959. I've learned since that we have between 12 - 15 years of B12 "reserve" in our bodies but I wasn't actually diagnosed with P.A. until 13 years later in 1972 by which time I was a staggering "Zombie".

Forty-four years on I cannot now remember how long it took me to get back to any semblance of normality but it certainly wasn't overnight, or a week. or a month, but if it is B12 deficiency or P.A. which you are suffering from the symptoms will improve - over time and you are certainly not doing yourself any harm by supplementing.

Please try to stop being so anxious and look forward to feeling better even if at first you may seem to be worse - you won't be the first or last person to experience this.

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Thank you for your reassurance.

It's hard to pinpoint when the problems truly started.

In March 2016 I just came over all faint and weak one afternoon-and it hasn't gone since. A few weeks later, between many doctor's appointments, I developed joint pain.

I think there have been clues for a few years - frequent urination, tiredness (beyond what would be expected but tiredness is hard to measure; I needed a nap every day, sometimes sleeping on the sofa at work during my lunchbreak). This has been for 3 or 4 years. Three years ago I also developed tinnitus - but I use headphones and also worked in nightclubs as a photographer so I don't know if any of these triggered my tinnitus or if it was the start of my problems with B12. My tinnitus has worsened in recent weeks.

I've also had an increasingly temperamental stomach in the last 2-3 years- often feeling bloated, full or nauseous for no apparent reason.

I don't get a sense that I've been unwell for as long as some others - perhaps 2-3 years.

My sick pay runs out soon - I am off work with the faintness, dizziness and weak legs. The thought of getting into financial trouble also drives my desperation and impatience.

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Are you taking hydroxo, cyano or methyl cobalamine? Find out what is better for you, maybe this one doesn't work for you. What about your iron stores? The treatment increases the demand of iron so you should check it. About my treatment, after one week (seven injections) I was very good, mainly energy. But, I don't know why, my symptoms came back about one month I felt amazing. I'm going to begin another and change some points. I hope you get better soon.


viniciuspaiva08 -thank you :)

I'm on hydroxo injections, methyl sublinguals. I don't know how long to give them until I decide that I don't think it's working. Others have mentioned weeks-months.

Iron was OK in my last test...I'm taking a multivitamin with iron as well, and eating lots of lentils and chickpeas!

Fatigue is less of an issue now-it is the dizziness/faintness which I am desperate to see the back of! I don't know if this is a stubborn neuro-symptom or something else...


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