Feeling worse after loading dose. - Pernicious Anaemi...

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Feeling worse after loading dose.

Moobear2 profile image

Hi everyone.

I posted the other week about my loading dose and feeling unwell.

Quick cover of what’s happened.

I had covid in Jan. Felt unwell after. Exhausted. Shortness of breath. Tingling in feet and hands. Very occasionally chest pains. Was originally told long covid. But a blood test was done and low b12 and iron. Never told exact figures. But blamed it on covid as covid strips people of b12 the gp said.

Was giving the loading dose of 6 b12 injection every other day. Last dose 10th September. While I had the loading dose made me feel shakey and unwell.

Two days after loading dose ended up in a and e thinking I was having a heart attack. I wasn’t but felt awful. Felt jittery and anxious. When they did the blood test to check for other things told me my b12 was high. Again not sure what figures.

It’s now 4 weeks since loading dose. And still l don’t feel right. Having a bad day today.

Don’t feel exhausted. But still feel breathless and now new symptoms of chest pains, strong palpitations, and really anxious which I didn’t have before. Keep getting a burning sensation in one foot.

This has really put me off the b12.

Can anyone give me some reassurance. My gp isn’t interested in any of my post b12 symptoms.

Is what I’m feeling the body repairing itself?

From what I’ve read on here most feel better after b12. I wasn’t that ill before the b12 other than being tired.

I feel since the injections I’ve gone so downhill.

Is this normal?

Thanks 😊

16 Replies

Hi Moobear2,

Welcome here, I’m so sorry to hear this. Please ask for print outs of your blood results. You can get worse before better but at the same time please do not put everything down to B12 deficiency and iron.

I am not that knowledgeable but there’s plenty on here who are. I am sure they will reply in due course.

Best wishes.

Moobear2 profile image
Moobear2 in reply to Narwhal10

Thanks for the reply 😊 My gp wouldn’t give me results of bloods. So I’ve not actually seen what levels are.

Just trusted them and went along for the loading dose. I just feel really anxious today. But I had no anxiety issues before the b12.

I don’t know if my b12 symptoms was delayed and showing now after loading dose.

As I felt quite well before the loading dose other than I was tired and getting pins and needles. Feeling a little breathless.

But now I feel awful.

Maybe I have just Given myself anxiety with it all.

Nackapan profile image
Nackapan in reply to Moobear2

You have a right to hsve your results. They used yo be just printed off for me.

I now have to fill out a form every time. Then told io yo s 30 day wait.

Ludicrous. J put on the form gir future use . Not allowed.

As if not enough admin. !!

You could get the NHs app if in the UK.

Agsin nit made easy buf cxn get access ic last 6 months results. Also consults.

B12 is the energy vitamin, it can make you feel anxious, a lot of people on here have had the same reaction, including me, I cut right down on how often I take it

Narwhal10 profile image
Narwhal10 in reply to Moobear2

Hi Moobear2,

Your Blood results are legally yours - practice managers and receptionists are more helpful.

I’m really sorry to hear you are anxious today. B12 is needed in the erm 300 trillion cells in our body (hope I’ve remembered that correctly). So lots of bodily systems are being repaired especially the nervous system. You might feel ‘jangled’. Monitor your symptoms and take it one day at a time.

Best wishes

I woulfnt say' normal.' But loading doses of b12 certainly shook up my nervous system. I was however very ill before injections. I did get worse.

Anxiety attacks. Migraines tinnitus the extras.

On the 5th week after loading j wad back at the doctors almost begging fir more b12 as nothing else found wrong with me. I was put back on every

Other day.

That was Dec. And by the end if Jan. (19) I started to see improvements.

Tough if you didn't have many symptoms before b12 injections.

Ask for bloods be repeated 4monthly or sooner mske sure nothing else is out of kilter or going on.

When is the next b12 supposed to be?

Long covud sbd b12 deficiency fo give similar symptoms

Moobear2 profile image
Moobear2 in reply to Nackapan

Thank you for reply. They wouldn’t even see me in person for so long in my gp. Had to keep ringing.

Ah yes in uk so might try nhs app.

Yeah I think it’s harder as had a read few and most had really bad symptoms before so could see a improvement afterwards. Where for me other way round. I didn’t even realise I had it, and my symptoms before was not stopping me going to work etc

Was just tired.

Since I’ve had the b12 I’ve had to take time off work with chest pains etc

I was suppose to have them every 3 months so 10th December. But they a and e doctor said I wouldn’t need anymore as my b12 was reading high after loading dose so not sure what will happen. Getting a appointment in my gp is really hard. They don’t want to see anyone in person so just been left to get on with it.

Nackapan profile image
Nackapan in reply to Moobear2

Yes it's awful. A high reading after injections is to be expected.

Shoukdnt actually be tested.

Means nothing.

You should be treated on symptoms and be on a maintenence regime.

I was supposed to have thrm 3 monthly too.

Never got to 3 months.

See how you go.

Hopefully get one st least 2 monthly if it's enough for you.

BNF guidelines.

They csn prescribe on sn individual basis in the best interest of a patient.

If neurological symptoms every other day until no more improvement.

I'm at present on a prescription of 2 weekly .

Keep a symptom diary perhaps.

T c

Moobear2 profile image
Moobear2 in reply to Nackapan

Thank you for all your help. Feels it’s harder as got all these symptoms after so I don’t know if it’s working or not really. As not got much apart from feeling tired to compare it too.

Definitely going to try get my blood results to see what my levels was to begin with.


I'm sorry to hear about your useless GP! Sadly, where B12 is concerned they are often ill informed. Doing your own research is the right thing to do!

When you first start B12 injections, it can be tough (I know it was for me), it takes your body a long time to become deficient, and it may take a little while to see the improvement you need.

Every vitamin has a 'cofactor' or something it needs to work with. For B12 it is folate. B12 cannot work without it. So if your doctor hasn't already prescribed some, get yourself folate tablets.

Also, during your first month of injections, your potassium levels can drop. Keep potassium rich foods nearby and top up with them when you can. Coconut water is great for this! Get some as soon as you can and see how you feel after a good drink.

Your ferritin levels (the iron stored in your liver) are also important. As once your system has the B12 it has been missing, it will be producing healthy red blood cells again. Make sure your diet has iron rich foods or take a gentle iron top up such as spatone.

Sometimes people's B12 deficiency symptoms worsen before getting better, this is your body healing. Stick with it, if you are worried, post again. There are thousands of us who have been in the same boat. How is your B12 deficiency being managed going forward? As a lot of GP's suggest one injection every 3/4 months, which is just enough to keep you alive, but won't actually allow your body to heal.

Keep in touch and let us know how you are getting on. You are not alone!

I get more tingling after b12 injections but have never had chest pains or palpitations. If these continue I would ask your Gp to investigate those. Covid seems to affect the body in many ways. They can start with a ecg often done at the surgery. If you didn’t have b12 problems prior to having covid then maybe possibly you won’t need b12 injections long term. Of course if you have never had your b12 measured before then you wouldn’t know if you had low b12 levels before having covid. It would be a good idea to get your b12/folate/ferritin measured every three months. If there is a steady downward trend in your b12 levels it might suggest you are having problems absorbing it in which case you may need injections or tablets long term depending on the cause. Many people can’t absorb b12 from the digestive system into the blood because they have PA which means they don’t have enough intrinsic factor protein to combine with the b12 in their food so it can be absorbed but there are other causes for not enough b12 being absorbed. Are you vegetarian /coeliac or taking ppis( acid suppressing medication eg omeprazole)? You have a right to your medical records so ask again about your blood results. I hope you start to feel better soon.

Your story is very similar to mine. I had covid back in march last year, initially recovered but felt tired, "off" somehow. Then, two months back, my doctor tested me for b12 deficiency; serum normal, homocystein normal, but mma elevated, but no cause for poor food absorbtion was found. With treatment all kinds off symptoms emerged, so i understand your frustration and worry; thinking that you're gonna feel better but instead get worse just sucks. I hope it gets better soon for both of us.

As other have noted, keep track of folate, iron and potassium. Also, any potential problem with absorbtion should be properly investigated. Best of luck!

Thanks for all the reply’s.I have had a holter monitor fitted (24 hour ECG) and need to wait for results. But been told it may be Postural tachycardia syndrome.

Not sure if anyone else suffered from this as I’m new to this site.

As when answering questions I’ve realised my heart rate goes really high when standing moving about. And comes back down on sitting.

Waiting for a few more checks to be done.

I’m not sure if POTS is a symptom of low b12.

Hi Moobear2, is it possible that you are experiencing panic attacks. At the start of lock down my regular B12 jabs were interrupted and irregular. I started getting anxious and occasionally experienced a tight chest with difficulty breathing and my heart felt and sounded like it was going to burst out of my chest. Luckily for me I recognised that this was due to a panic attack, as I have experienced them before.

For me, the anxiety lead to a panic attack, the panic attack symptoms make you feel like you are about to die, which makes you panic even more.

What I didn't understand was why I was having them, as it would happen out of the blue, in non-stressful situations without any reason. If it could be panic attacks you are experiencing, I have learned a breathing technique which works very well, take a deep breath, hold it for a few seconds, breath out, repeat. Apparently it tricks the brain in some way and helps you to calm down an the panic attack subsides.

Since my B12 jab routine has been back to normal, I've felt fine, so can only assume it was B12 related, or the lack of to be more precise.

I hope you start to feel better soon.

Moobear2 profile image
Moobear2 in reply to Adsypadsy

Thanks for reply. This is what I thought. But I only get high heart rate while moving standing. Goes back to normal as soon as a sit. No matter what the situation so they’ve now ruled out panic attacks.

I have had covid in jan and apparently people have had POTS from covid.

Also low b12 can cause POTs.

It’s not good as my job is a dental nurse and moving about a lot. I’m ok as soon as I sit but for instant all morning today heartrate sat at 145 until I sat down which is hard to do. I’m struggling and only able to cope with mornings in work.

Little update. So been to see GP. Did some checks and definitely thinks it’s Postural orthostatic tachycardia syndrome. They don’t think it’s any relation to b12. Just coincidence it started after loading dose.

They think it’s down to covid or reaction to the covid vaccines that have caused it.

I’m being referred for a tilt table test to confirm it before being giving any medication.

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