Pernicious Anaemia Society
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B12 injection dosage

Hi there

I was diagnosed with PA around January and had my 6 loading injections of cyanocobalamin ending 11 days ago. Now I am prescribed monthly injections. I was also anemic at the time I was diagnosed. 4 days ago I started getting headaches, nosebleeds, feeling dizzy, fatigued, and like I'm in a dream. I am just wondering, is this because I don't have high enough b12 levels to go more than a week without an injection? Is there a way to help not feel so poorly? Any advice helps. Thank you!

4 Replies

I'm wondering if you have had your Folate tested as this is essential to process the B12


I have not had my folate checked. I assume it's alright because I felt well after my 5th and 6th week loading injections. The symptoms of PA just came back after that week passed.


It is not uncommon for some symptoms to appear to get worse before they get better as the B12 starts to repair the damage done caused by the deficiency.

Hopefully your symptoms will ease as your body "gets used" to the replenished B12 in your system. Try not to worry too much as stress only uses up the B12 quicker.

Folate gets used up processing the B12 so you need to have a healthy level of it.

"Folic acid works closely with vitamin B12 in making red blood cells and helps iron function properly in the body. Vitamin B9 works with vitamins B6 and B12 and other nutrients in controlling the blood levels of the amino acid homocysteine.

Rich sources of folate include spinach, dark leafy greens, asparagus, turnip, beets, and mustard greens, Brussels sprouts, soybeans, beef liver, brewer's yeast, root vegetables, whole grains, wheat germ, bulgur wheat, kidney beans, white beans, salmon, orange juice, avocado, and milk. In addition, all grain and cereal products in the US are fortified with folic acid".

Vitamin B9 (Folic acid) University of Maryland Medical Centre

As you are on cyanocobamalin I guess you are not in the UK - are you in the U.S?

You say you were "also anemic at the time I was diagnosed. 4 days ago" have you been prescribed anything for that?

I am not a medically qualified person but I have had P.A. for 45 years and I have personally taken 1 – Folic Acid 400μg tablet every day for more years than I can remember as a "maintenance" dose. This is in addition to what is already fortified in my every day breakfast cereals. I too am on cyano, originally every four weeks, like yourself, but lately managed to persuade my doctor to increase the frequency to every three weeks due to the return of some symptoms in the run up to the next injection.

I wish you well


Thank you for your advice! I am in the US. I meant that I was anemic when I was diagnosed with PA 2 months ago. I have been taking an iron supplement with the b12 injections.


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