Pernicious Anaemia Society

2 Month B12 Injections

I visited the GP to explain about the re- occurence of Migraine Frequency

towards in the 2 month mark of the 3 mth B12 injections and explained waking with numb hands.

The GP has said after this weeks injection have a Blood Test for B12 in 1 month time.

(Which i think would be too soon) this is to help asses with regards to changing to a 2 monthly injection.But if i get a high B12 this could also go against me rather than going by my symptoms,which i have heard many times on the forum.

Would anyone agree with this that it would be too soon?

4 Replies


I'm surprised that the GP wants to test your B12 levels.

I think the BSH Cobalamin and Folate Guidelines mentions that testing after b12 supplementation has started is irrelevant. Has your GP seen BSH Cobalamin guidelines?

Neurological Symptoms

I thought that migraine counted as a neurological symptom (I saw a neurologist about unusual migraine symptoms). If you have neurological symptoms, I don't know why you are on the standard UK treatment of a maintenance injection every 3 months.

Link below outlines Uk b12 treatment including treatment for those with B12 deficiency with neuro symptoms which is more intensive than you appear to be getting.

B12 Deficiency Symptoms lists

pernicious-anaemia-society.... see Checklist


Hi sleepybunny ,

thank you for your reply which is very helpful and

thanks for providing the links.

It is taking such a long time to get my GP's to agree to a 2 monthly injection but i am have patience and will keep pushing for it but a blood test is just a block i feel .Even today i said to GP that B12 is water soluble and was asked what does that mean! Without me this time including the sentence you cannot overdose on it!Which they always disagree with me on.They should be treating me every 2 months with the return of pins and needles on waking in the early hours and rapid amount of returning Migraine Auras .I have shown each GP the BSH cobalamin copies and each time they always look blankly at me and talk about overdosing on B12 and only authorised to give 4 injections a year

as i only have B12 deficiancy not PA but never consider my Symptoms which is most important.I have tried Magnesium Bisglycinate 150mg twice a day which is helpful in reducing migraine by 50% .

Thanks for your support and generous time too.


"I have shown each GP the BSH cobalamin copies "

My personal experience is that GPs take more notice of written letters. My understanding is that letters to GP have to be filed with medical records so are a record of issues being raised.

Link below about writing letters to GPs about b12 deficiency Point 1 might be relevant

"talk about overdosing on B12 and only authorised to give 4 injections a year"

I'd also recommend reading fbirder 's summary of B12 documents. Lots of useful quotes from b12 documents. Link to his summary in third pinned post on forum.

My understanding of the advice in BNF (British National Formulary) is that GPs are authorised to give injections more than 4 times a year if a patient is b12 deficient with neurological symptoms.

I take the BNF info with me to appts in case I get a comment similar to the one you had.


Hi sleepybunny thank you for all your support it is very generous of you ,i will follow your advice and challenge the GP's ,you have made very good points i will read fbirder's summary .

Again Very helpful advice ,thanks.


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