Pernicious Anaemia Society
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Feel sick and dizzy!!

So I went to London today, for my 5th or maybe 6th Hydroxocobalamin shot, I have been suffering the worst headaches and dizzy spells for the past 2 weeks.

Quick history.

I Reported to my Dr 10 weeks ago, with symptoms of b12 deficiency.

Bloods came back 'normal'. Not P.A. apparently.

Booked to see a neurologist (privately as couldn't wait the 4 month waiting list)

He has referred me for a brain and spine scan (suspected SACD or myeloneuropathy) and 'recommended' on an empirical basis that my Dr administer b12 shots.

My Dr is currently refusing until they have had a multi-disciplinary meeting about it. so that's dragged it out until the new year now. Meanwhile I'm suffering all over christmas.

So, out of desperation, I have been going twice weekly to get hydroxocobalamin shots. However in the past 2 weeks, i have started feeling really dizzy and had a headache that just will not go away. I have taken ibuprofen, Anadin, Aspirin, and Paracetamol. And nothing has touched it. It doesn't even feel like a headache so much anymore. More like, you know when you have flu or a heavy cold and you go out into the cold without a hat on, and your head feels really tingly. Well, like that. I have also since I returned home, felt very nauseous. My feet are freezing cold, but sweating, and keep cramping.

I don't know whats happening but it doesn't feel good. I attended A&E out of desperation with these symptoms, (only not so bad) last week and they said there's nothing they can do for me. Only a neurologist can help me.

What am I going to do? My Dr's is closed now for 3 days. And i'm scared. I've felt very vague for the past couple of weeks also, and my vision blurs occasionally and I struggle to focus when trying to read anything.

I don't know i should be having methylcobalamin, or cyanocobalamin or what.

I hate my Doctor :(

16 Replies


I experienced strong headache, nausea and acne when I took too much B12 (oral pills).

When I started to supplement just after I discovered my B12D was severe (138), I could handle taking 2000 mcg/day. Now, almost 2.5/3 months later, I take 250 mcg a day: if I take more I experiment side effects, if I take less symptoms of B12D come back. I assume I'll have to reduce again in a few weeks.

Concerning the vision blurring, this has been both a B12 deficiency symptom and a B12 "overdose"

symptom when I took too much B12 pills.

You should probably stop B12 injections for 1 or 2 weeks to see if you feel better.

Good luck!


Thankyou for the reply Marybrown,

Sometimes it just helps to reduce the anxiety, just getting some information from people who have walked in your shoes, as it were. Hopefully it's just due to a b12 imbalance, or similar. Just got to get through the next 3 nights till I can see my GP, or maybe get in touch with my neurologist.

I think everyone on here knows what 3 days feels like though. :/

Thanks again. Hope you're managing to get through the festive period ok.

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I just thought about it reading the other answers: at the beginning (during the first month of supplementation), I remember I took some stuff that helped me feel better: magnesium (drinking nigari solution), potassium (eating plenty of banana and coconut milk), folate (eating greens and salad), iron, etc.

But when I saw that my banana in coconut milk did not help with my headache and nausea, the efficient solution was to reduce my B12 daily supplements.

I really hope you will feel better soon! Let us know how you feel in a few days, good luck!


Great. Thanks for all the tips. I'll look into the magnesium option. I do try to eat a banana a day, and I had read somewhere about coconut water, and had some of that for a few days. but haven't restocked over Christmas. I'll grab some of that too.

The plus side of the b12 shot is the symptoms of pins and needles/numbness upon wakening seem to reduce. But the morning after I tend to wake with an almighty headache. Although I've also been informed that I snore pretty excessively on nights after a shot too. So maybe the headache is being caused by sleeping so heavy. I do feel like I've been knocked out with a bat, the next morning.

I'll be sure to report back in a few days. Thanks.

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Hi Dan10 was your Folate level tested?

It is important that your Folate level is monitored as this is essential to process the B12 you are having injected.

There is a complex interaction between folic acid, vitamin B12 and iron. A deficiency of one may be "masked" by excess of another so the three must always be in balance.

Symptoms of a folate deficiency can include:

symptoms related to anaemia

reduced sense of taste


numbness and tingling in the feet and hands

muscle weakness


Folic acid works closely with vitamin B12 in making red blood cells and helps iron function properly in the body.

It is not uncommon for some symptoms to appear to get worse before they get better as the B12 starts repairing the damage done to your nervous system and your brain starts getting multiple messages from part of the body it had "forgotten about" or lost contact with.

I sometimes liken it to a badly tuned radio on which you have turned the volume up high trying to catch the programme you want when all of a sudden the signal comes in loud and clear and the blast nearly deafens you.

A lot will depend on the severity and longevity of your B12 deficiency as to how long before there is no further improvement or recovery.

Some symptoms will "disappear" quite quickly whereas others may take months or even years. There is no set timescale as we are all different.

I am not a medically trained person but I've had P.A. (a form of B12 deficiency) for more than 45 years.

I wish you well



Thankyou. yes my folate levels were fine. I'm still supplementing occasionally though. Not every day, but I took one earlier. and tried to drink plenty of water. AND i've had a decent dinner, which I think may have been a contributory factor. Hadn't eaten much today. Still feel pretty terrible, but I'm bearing with it, as you do. Just wish I knew I would wake up in the morning feeling better, but that's rarely the case these days.

Helps knowing i'm not alone though, so thanks again.

Great metaphor by the way :)

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I feel terrible initially after injections take folic acid and drink coconut water and after a week I’m good to go . I continue with folic acid as if don’t take for a few days become dizzy and feel like ants are invading my brain .

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I've been OK up till now, well I thought I was, but maybe thats what this is side effects of the shots. I hope so rather than whatever the underlying cause is, is getting worse. That I definitely don't want :/

Thanks Av.



Sometimes people can experience a drop in potassium levels when they start b12 treatment. Have your potassium levels been checked? See Side Effects section


Thankyou SB.

I am eating a banana as we speak. Hopefully more will be revealed after my scans and further bloods.


Hi Dan I have recently been through similar circumstances. I have fibromyalgia and wasn't feeling very great. I saw a locum GP and he decided to do blood tests. B12 and foliate deficiency were picked up and I received a course of 6 injections straight away and given folic acid daily. Sometimes after the jab my head did feel strange but calmed down. I had been experiencing strange heady feelings for a while pre injections. I am a migraine sufferer but it wasn't the same. Taking the folic acid everyday seems to ease this feeling in my head. If I stop taking for a few days it starts to come back. I am due for another jab B12 on 3rd January which is 3 month follow up. I had been making sure to eat plenty greens everyday and I had a banana and/or porridge or oats of some kind too. I wasn't a big egg eater but to get extra protein I was trying that too. That was until recently, I was very ill 3 weeks ago and haven't been able to eat much at all as I've been diagnosed with gallstones. I have never had pain like it. I'm back to square one. I was jaundiced and bloods are being checked twice a week as everything is haywire now. Waiting to see a surgeon. 12 week cycle just for an appointment offer. Never rains but it pours. I will see how it goes after this next injection. I really need a boost of something to make me feel a bit better. ☺ everyone is different and treatments affect us all in different ways. I'm sure you will get sorted out. We are ever hopeful.😀


Thanks Christa,

My b12 and folate are ok. I’m doing most of what you recommend also. So hopefully soon I will find the right balance.

I had gallstones a few years ago, and ended up having my gallbladder removed. I know exactly what you mean about the pain, it’s extreme to say the least. On the plus side, once you have your gallbladder removed it will all be over.

Unlike this guessing game of a condition, that is all consuming!!

Hope you get sorted soon.


I started having terrible headaches, stomach aches and insomnia after my b12 shots. I saw an allergist two days ago who told me he thought I had something called flushing syndrome. Try taking antihistamines before and for a couple of days after you get your shot. Benadryl has really worked to alleviate these symptoms for me. My allergist told me that I'm not allergic to the B12 shots but people with flushing syndrome for some reason have over reactions to some things like heat, exercise, wine, chocolate and for me apparently B12 shots. He recommended I talk to my GP about taking beta blockers on the day I receive my shots. I'm going to call my doctor after the new year and talk to him about this.


Thanks moKay, I might try this out. It really is a trial and error thing isn’t it.


I forgot to say in my last reply that the main symptom people with flushing syndrome have is their face turns bright red and feels like a bad sunburn. This is caused by your body reacting to the substance or heat or stress by releasing a large amount of cortisol into your bloodstream. I hope this helps.


Hi when I first started getting my injections I felt terrible dizzy , bad migraine etc I had to stop the injections for a while. I had such terrible vertigo as well. I started the injections back up and I take folate not folic acid as I found that that was giving me a bad head. I also went and had the epley manoeuvre for the dizziness which really helped as I was getting terrible vertigo bouts every couple of months this seems to have gone now . I still get bad migraine every so often but when I look back I think it was the b12 deficiency all along. Sumatriptan has worked really well for me for migraine, when nothing else did. Hope you get it sorted .


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