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Pernicious Anaemia Society
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Vitamin b12 injections and folic acid tabs?

Hi I have pernicious anaemia and receive vit b12 injections recently been very poorly both physically and mentally went to docs explaining all my new symptoms having no idea what was wrong with me so tired and hurting all over and a whole list of ailments anyway got bloods done and got phone call next morning was told my folate levels were 1.8 and average normal person is 20 so given folic acid tabs but I've just read the leaflet and it states do not take if you have vit b12 deficiency including pernicious anaemia or any other blood disorder. Does anyone know why? I have only recently started to really try and understand this disorder and read more about it as my symptoms have got so much worse...

13 Replies

There's a bit of information in the Management section in this link.


I found the "BCSH Cobalamin and Folate Guidelines" useful to read. It discusses folate deficiency.


Hi Bernadette0141

The "Patient" website Sleepbunny recommended reads:

"Folic acid may produce a haematological response in vitamin B12 deficiency but may aggravate the neuropathy and also precipitate subacute combined degeneration of the spinal cord. Large doses of folic acid alone should therefore not be used to treat megaloblastic anaemia unless the serum vitamin B12 level is known to be normal.

Not sure if I'm reading this right as I'm not a "medical person" but as you say you are on b12 injections your "serum level" can be "assumed" to be "normal" (i.e. not deficient) so it should be OK to take the folic acid tablets as prescribed by your GP.

But if you're still worried speak to you doctor or (maybe better and easier) your pharmacist.

I've had P.A. for nigh on 45 years and take 400ug folic acid every day and I'm still "clivealive" coming up to 75.

I wish you well for the future.


Thankyou for your most helpful information I am now on folic acid but will be finding out more about my blood results this wk. Thanks again


Hi Bernadette, I am similar to you chronically tired with widespread pain. I have PA only diagnosed 1year I have injections every 4 weeks as I'm lucky to have a doctor who allows this. My brain fog improved but I still have problems concentrating and remembering things, I reached a stage that resembled dementia which resulted in a diagnosis of PA. This week I have been told I have fibromyalgia. I thought my symptoms were from damage caused by several years of undiagnosed PA but watching a documentary on Fibro suggested by my GP I now think he could be right as it is describing my symptoms. It's all very confusing and a worry as I was always such an active person and although I still try to be it just brings on a flare up which can last for weeks if I overdo it. I think once you start injections it is taken for granted by many GPs that any symptoms you have are no longer PA related which I disagree with i think it takes much longer for damage to heal. I hope once they sort your folate out you feel a little better. I find this site amazing the people are so informative I find it a great help.


Hi thanks so much for your reply I have same symptoms as yourself I wake up in excruciating pain from sleep it starts from my neck all down my arms even into my hands lower back legs and even the soles of my foot in in agony all day and usually have to swallow painkillers but once the pain dulls and painkillers wear of I feel they mask my symptoms and hate the thought of what they are doing to my liver/kidneys so I'm now trying not to be dependant on them but I'm in agony and dread going to bed as I know I will again wake up in pain. I have always suffered back pain but this is another level so I feel this is maybe to do with my b12 deficiency?


Your body needs folate to process B12.

The previous BCHS guidelines on folate and B12 deficiency were ambiguous in advice concerning circumstances where there are both folate and B12 deficiencies present and it was quite easy to read them as saying you should not treat a folate deficiency if there was a B12 deficiency when actually you need both.

Supplementing folic acid is known to mask one of the classic symptoms of a B12 deficiency - macrocytosis - which may lead to delays in diagnosis and the risk of neurological symptoms going untreated so long that the damage becomes permanent.

This was the reason for the warning on using folic acid. Unfortunately the confusion is still out there.

20 is actually the top end of the normal range - which goes down to around 4 - most likely reason that you have become deficient is that your body has used up a lot of folate processing the B12 you have received. The best form of folate is actually from food but at the levels you have you need to get levels up quickly.

Has your doctor also talked to you about diet and trying to up your intake of folate rick foods.


Hi thankyou so much for your most helpful information I am now going to ask my GP advice on diet and folate rich foods as you recommended I have not been very knowledgeable to pernicious anaemia but have been trying to educate myself more in order to understand my symptoms more so again thanks for your informative advice.


Hi Burnadette,

I was diagnosed with PA 17 years ago. I have B12 inj every 3 weeks or more often if needed. I also take 5mg folic acid daily. I also find i need to take 50mg of the other B vitamins daily.


Thankyou for your reply I am now looking into other ways to up my vitamin B intake.


Your folate levels need to be about twenty , otherwise your B12 will not become active .

It will be useless and just be excreceted out of you. You will feel no benefit whatsoever of your injections , that is why you will have been feeling so poorly. You need to be on folic acid 5mg daily to supplement your injections .

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Thankyou so much for your reply I have since been prescribed folic acid and have been taking them for about a week now so don't feel any difference yet but my injection is due next wk so hoping will now get the benefit from it.


Is 5 mg the recommended dose? My biggest symptoms right. And despite just giving myself a shot of cyano I have tingling in hands and feet and shortness of breath which has been persisting for days.. feels like a never ending anxiety attack


This is a great resource: b12d.org/


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