Pernicious Anaemia Society

Breathing difficulties

Hi - I am new to this forum (female 45) but would value your advice. In summary, my B12 deficiency (152) has been identified following referral to a Neurologist after symptoms including tremor and poor memory etc. I have received 3 out of the 6 loading doses (3rd one last Friday) prescribed over 2 weeks but yesterday developed tightness in my chest and breathing difficulties and ended up in A&E. Thankfully I've been given a clean bill of health but am scared to continue with the injections this week as I am concerned they may have caused this and it could get worse. I still feel I can't get enough air but the GP today has dismissed any link to the injections. I don't take any other medications and had been looking forward to having the injections so had not been anxious at all. Only other thing to mention is that my skin and eyes were itching following the second injection so I had taken an anti-histamine. Any advice or similar experiences would be most gratefully received. Thank you.

17 Replies

Hi Colb53 have you had your Folate level checked?

Ironically some symptoms of B12 Deficiency can appear to get worse before they get better as the B12 you are having injected gets to work repairing the damage done to your nervous system. Hopefully these will ease in time.

I'm not a medically qualified person but one who has had P.A. for 45 years and my breathing difficulties can get worse in the run up to my next injection.

I wish you well.


Thank you clivealive - I really appreciate you responding. My folate level was normal apparently. I have read a little about the need to take the two together but assume I don't need to if my folate is normal?

I panicked yesterday when I couldn't breathe and obviously made things worse. It's all been put down to anxiety which I didn't have before the injections. I didn't have the injection today because I was too scared. The next one is due Wednesday. In your opinion, could I have had too much if my level was 152 to start? I've never experienced breathlessness :-(


I do hope Colb53 that Foggyme has set your mind at rest with her wise and comprehensive advice far better than I ever could.

It might be a good idea to chat with your doctor about your Folate level as I understand it it gets "used up" by the B12.

I've taken 1 – Folic Acid 400μg tablet every day for as long as I can remember plus another 200μg included in an "Over 70s" general supplement as well as what is fortified in my daily breakfast cereals of All Bran and Grape Nuts yet my level was still only mid range. Mind you I have my B12 injections of cyanocobamalin 1000mcg every three weeks now.

I do hope things settle down for you - the main thing is not to get too stressed out about it and become a patient patient. You are on the road to recovery.


Hi Colb53. clivealive is right. When injections of B12 commence, many people say that their symptoms appear to feel worse before they start getting better. This is because repair is starting to take place as all your cells get the B12 they need and start to 'wake-up' (for want of a better word 😀).

Some people report having minor after effects from the injections (headache and facial rashes are the main ones) but these usually settle down overtime.'s possible that you have minor side effects from the injection rather than an allergic reaction (that would be much more severe and would have been instant).

If your input 'patient information leaflet for hydroxocobalamin' into Google, you'll be able to access all the information you need to know about the potential side effects of hydroxycobalamin. Don't let it put you off - they list every know side effect and not everybody gets a side effect.

Also - the side effects of Hydroxocobalamin are almost identical to the symptoms of B12 deficency.

So you may well have a combination of B12 deficency symptoms (some of which get worse when treatment commences), a temporary worsening of symptoms as the process of repair begins, or (and perhaps and) minor side effects from the Hydroxocobalamin which usually settle down.

The most important thing is to continue with the B12 injections. It's the only way that you'll be able to get and stay well. And you can never have too much B12: its not toxic, you can't overdose on it, 5,000 times the amount you have is given in to successive IV doses for carbon monoxide poisoning.

Here's a link to a document that may reassure you (backed up appropriate medical research):

About the shortness of breath: if you become short of breath all the time (and not just on exertion), your lips or fingers turn blue, you become pale and clammy, feel dizzy when sitting, become confused or have a raised temperature - then this is perhaps something beyond what you would 'normally' expect with B12 deficiency. If this were to occur you should seek emergency medical treatment, either from your GP (emergency same day appointment), walk in centre or, if concerned or its out of hours, go directly to A & E.

Finally, please try not to be anxious about the injections - they really are exactly what you need and once you've been on them for a while it'll become as routine as washing and dressing - and you'll have the energy to do both 😀.

Take care x


Thank you your comprehensive reply - it is very reassuring. I still have the tightness in my chest and still feel short of breath just sitting here, so it's a constant thing. The only relief is to be in the fresh air. I panicked yesterday and made it worse so I had tingling in both arms and thought I was going to pass out - I'm trying to tell myself I'm ok and I know that my blood pressure and oxygen levels were good yesterday when tested. It is making me really scared though. Would something like Quiet Life herbal tablets help me to get through this?


Hi Colb53. Am I right in assuming you saw a doctor yesterday (the BP and oxygen levels)? And that they are aware of the tightness in your chest?

It's really difficult to advise about something like this in a forum because so many variables come into play.

The best advice I can give is if your condition worsens (since you saw your GP) then seek immediate medical advice. Or if you fail to improve in the next few days, then it would perhaps be advisable to see your GP again.

It sounds as if you may have been told that you are suffering from panic attacks? However, it would not be usual to have permenant tightness in the chest with this - this would only usually occur during a panic attack and would disappear once the attack is over.

The pins and needles may be due to episodes of over breathing - most certainly they will be if they wear off once breathing has settled down again.

I know how frightening this must be for you and how anxious it must be making you feel (how can it not). Some people here say that meditation helps - 'mindfulness' is one (deatails on the internet) - perhaps this might be something that would help you over this sticky patch?

Quiet Life Herbal Tablets? Don't know - personnaly I wouldn't. No idea what's in them and some supplements can interact or interfere with the actions of other medications.

Relaxation, anti-anxiety measures, treatment for your B12 deficiency, support from others (include us in that) and knowing when and how to get further medical advice will help a lot.

It would also be a good idea to read the PAS pinned posts to the right of this page when you log on. There's lots of information about b12 deficiency that you will find helpful and many people say that understand the condition and becoming more knowledgable helps them to feel less frightened and more in control.

Really do hope you start to feel better very soon and just post again if you're worried or need more help.

Take care x


Thank you again. Yes I was thoroughly checked out in A&E - bloods, heart trace, chest xray. All fine. I went for my B12 appointment today and told nurse what happened and how I am feeling so then saw GP who just listened to my breathing and heart and said all ok and to continue with injection or give it a few days (which is what I decided).

I appreciate it's difficult so I will seek further help if I need to. I'm sucking menthol sweets now to try and open the airways to save me freezing outside trying to get air!

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Just a thought...have you been tested for asthma?

Might be worth asking you GP or surgery nurse to do what's called a reversibility test.



No I haven't but my daughter has asthma so I took a puff of her ventolin on way to A&E yesterday. I was in such a state I'm not sure if it helped. I will ask the nurse though for that test - thanks again

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This may sound strange, but I've got a little handheld fan that I use, also when I'm having a hot sweet moment as peri menapausal.

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Breathing difficulties can happen if you have loading doses like 3 per week or 6 over 2 weeks.

It's too much B12 too fast.

You need more time between injections.

The first time I had loading doses I had breathing difficulties so I cut back to 1 per week for the next few loading doses, was starting to feel much better.

The next time my B12 was low and had to have loading doses my GP recommended 1 per week for 6wks and all was fine, no problems.

I did try more than 1 per week just to make sure and started having breathing difficulties again by 3rd injection, so it's most likely that.

I think you should also be taking Folic acid when you're on injections as it goes hand in hand with B12 but you can ask your GP about that. It's normally 400ug tablet daily.

Hope feel better soon.

It is an effect from the injections, Don't worry it will go away just have more gap in loading doses so it's introduced to your body slower. (1 per week)

Hope this helps.

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Many thanks Ryaan - this makes sense. I ended up having the 6 in 2 weeks but still getting the breathing issue intermittently. Hopefully it will settle soon, as I had last loading injection on 23rd January. Thanks again!


I had awful breathing problems when I first started getting treatment. It felt like I had to keep reminding and forcing myself to breathe or I would just stop. I also kept waking during the night with a tight chest and feeling short of breath. It was like I couldn't fill my lungs with air properly - a bit scary really but I guess there was some damage that needed to be repaired or maybe I needed to learn to breathe properly again after years of not being able to.

Thankfully it did eventually stop and I feel a thousand times better. I used to get occasional and mild bouts of breathlessness when I was on injections every 8 weeks, but now I have them monthly at the doctor's and self-inject at home as needed I've not had any more problems.

Its so hard when you first start out and things get worse isn't it? Especially as some people seem to magically improve from their very first injection - it made me wonder what was wrong with me! But I persevered with self-injecting and folate supplements (which I would strongly recommend) as well as a thyroid supplement and D3-K2 and now I feel so much better. Good luck! :)

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Thank you so much. I am sitting here bawling my eyes out after reading your post - that's exactly how I feel and today I've been feeling really anxious (I've never suffered with anxiety before) but feeling relieved now that I'm not going mad and it is real because you've experienced it as well. It terrifies me that it'll get worse if I keep going with the injections but I know I have to to get better.


I'm so glad it was helpful! The advice on this site helped me get through the first part of my treatment when I was struggling. It does sound like we had the same issues although obviously I would still get checked for other problems too - just in case. I hope it all goes well and you see the improvements you want soon. I feel like a new person and I bet you will too! :) X

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It's difficult to know what's going on. What you describe can also be a symptom of B12 deficiency so it's possible you would have progressed to this symptom as your PA got worse anyway. The sensation of a tight band around your chest/torso and being unable to get air into your lungs - I had that for a long time.

As the others have said, panic exacerbates it. I've found focusing on the out breath rather than getting air in is helpful in calming things down if panic is occurring. If you breathe out slowly and gently and allow the air back into your lungs without trying to suck it in, while telling yourself mentally everything is fine, that will help IF it is panic.

However we are not medics here, and while we can reassure with our own experiences we cannot diagnose. I suggest reminding your practice nurse at next injection so she is aware, and then waiting in your GP waiting room for a while after the injection until you are sure you are ok. And if you have problems after that then seek help as you did before. And follow up the asthma test. We know our own bodies.

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One of the symptoms of B12 deficiency is anxiety so it is possible the panic attacks / anxiety / general increase in stress (especially as you sound like it has been a bit of a journey to get treatment) may be related. If it gets worse I would seek medical attention again though - better safe than sorry.

If you think it may be related to anxiety / panic attacks / stress etc the website below (run by a Glasgow NHS health board) has various self help leaflets / audio resources that may help to explain what is going on. I went to a NHS run course (in another city) to support a family member (who was having heightened anxiety & panic attacks) which was in large part based on this series of booklets/ audio resources. It was very helpful to her... and for that matter me!

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