Pernicious Anaemia Society
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In the month since I joined this website, I noticed many reports of side effects by those receiving injections.

I purchased a vial of 1,000 mcgs of B12 with the doctor's prescription, that remains unused. I was not aware that cianocobalamin is not the only form of injectable B12So I have used sublingual strips of methylcobalamin.

But this afternoon I decided to open the package and reviewed the instructions. They are very helpful for patients to understand and be prepared for side effects. The manufacturer here in Canada does not have a website, thus I Googled until I located similar information. Next time you go to have your B12 shot ask the nurse to copy the pamphlet for you. Here's one that is helpful, note also it will decrease potassium levels in the blood and will interact with folic acid.

In good health,


Last Thursday I attended the GP's office to learn blood work results from Feb. 7. My ferritin level dropped from 18 to 17 in one month, despite 300 mcgs of expensive hematinic, lean meat or salmon twice a day. I felt discouraged, because feeling stronger is a priority for me.

Neither the puppy or the kitty know how to clean the house or go for groceries, let alone answer the telephone!

The results for intrinsic factor and parietal cells also from Feb. 7 were not yet available.

Will have to persist, for here the minimum ferritin is 11, and the maximum 190. I was hoping I would have reached 25, but not yet. The appointment with the hematologist is not until April 11.

12 Replies

Interestingly, the British National Formulary contains this statement under Cyanocobalamin:


The BP directs that when vitamin B12 injection is prescribed or demanded hydroxocobalamin injection shall be dispensed or supplied

UK residents can register for free and access BNF:

So, indeed, cyanocobalamin is not the only form!



Comment appreciated, Rod.

In Canada the only format available is cianocobalamin, however website of Mayo Clinic in the US shows, under Drugs/Vitamins for different conditions, both ciano and

methylcobalamin formats. The latter being the recommend form, but issue is purchasing from US websites costs the patient full price (US$45/50.00) plus shipping and VAT upon arrival at the Post Office. Last month it cost me Can$3.00 dispensing fee for drug cost only available through prescription, covered under provincial medical coverage.

When I learned through this website from "nostoneunturned" that the methyl form was recommended, I purchased sublingual strips from vitamin company, increasing dosage each day to maximum of 5,000 mcgs. One box with 30 strips of 1,000 mcgs costs 12.00 plus tax. The other day I found them at half price, and scooped up half dozen.

The pamphlet I reported reading earlier states that ïf a vit B12 deficiency is allowed to progress more than 3 months, permanent degenerative spinal cord lesions may occur, such lesions have been observed when folic acid is used as the sole hemaopoletic agent. In 2009 due to sciatica attack, it was determined that I had severe lumbar scoliosis, with disks deteriorated. Yet, 20 years earlier I had X-ray that showed a straight spine. I still have that picture.

But, I continue my search: if PA is ruled out through the blood work done on Feb. 7, then I have B12 and iron deficiencies. Some blood tests are not covered by either the provincial medical or private medical insurance. Acetylcholine receptor antibodies, the test for "miastenia gravis"is one of them. I paid $130,- to have it complated, for MA also has neurological symptoms.

Enjoy the weekend, winter is almost over.




I live in Aberdeen Scotland and I have only had four injections. However no side effects and believe me I usually have them all! I checked and I get Hydroxocobalamin which is indeed the most expensive of the three forms I know about! For once well done NHS!


Just a comment on your ferritin. I wouldn't stress about ferritin dropping by one point. Ferritin is what's called an acute phase reactant, and it can be elevated by inflammation and/or infection. I took iron supplements with plenty of red meat for three months, and in that time my ferritin fell from 19 to 14. At the same time, all the symptoms that I'd been having from the iron deficiency - and it was a long list from cold intolerance to night blindness to hair loss - cleared up. Also one point is such a small amount and I don't know if the test is that accurate.



My name is masum from Bangladesh. I am taking b12 injection 1000 from 4 months ago. But last weak I test b12 level. It was 1500up. What can I do now. I m very wary to see my ecg abnormal report. Before taking b12 ECG report was normal. Any one can advice me. Please. My email ID - My Bangladeshi doctor advice me to stop injection. But not give me answer for over b12 level.


Hi Masum:

This very informative site contains a lot of information about B12 doses and reactions.

Can you click on Questions, then on Recent Most Popular Questions and review question from cokey67 and all answers given. One reply made reference to B12 interfering with potassium levels, and that same issue appears in the link I provided in the blog I posted in the beginning of this chain. Is it possible that your abnormal ecg was the result of an inbalance?

With respect to B12 dosages, there are many replies providing information about the topic.

But, I am also curious as to the reason your doctor gave you B12 shots. What is your iron level? Low levels can also cause extreme fatigue.

The levels for B12 in Canada are stated as: >133 PMOL/L and my lab reports state: "Serum Vitamin B12 should be considered for assessment of peripheral neuropathy, megaloblastic anemia or malabsorptive conditions."

Good luck in your search.


hi mashby,

I am very happy for your reply, I have low level iron with b12. but doctor give me only b12 injection, is it right, when detected PA, my hemoglobin was 14.1, iron level 40 ug, but now hemoglobin is 12.5, iron not tested,,

have I take iron supplement with b12 injection?

I m sorry for my poor English

thank you


Hi Masum:

The reference levels for blood work vary from country to country. Without reference ranges for your location, it is not clear where your deficiencies are, and how to get them corrected.

So, I thought you might want to review this site, for the American Association of Laboratories,

that has numerous sites for different countries. I opened the link to Anemia, and suggest you review the material first. remember that in PA, the cells are macro, or larger than normal. But you can still have anemia like me, my cells are micro (smaller than regular size, thus carry less oxigen. The benefit of this site is that you can e-mail your question to them and a lab referral person will reply in a couple of days.


Oops, here is the link you will need, and I suggest you get a copy of your blood work reports and indicate your local reference ranges and your results plus dates.

Now it is your turn to wish me good luck. In less than 2 hours I will have my first appointment with a family doctor (five mos. wait), for here in Canada is difficult to find one, I have been using a walk-in clinic for the past five years. Also, on Thursday I have my first appointment with a hematologist (3 mos. wait) to review my ferritin (iron) levels and assist with bringing them up. Last reading showed my ferritin at 17, and the minimum in the reference range is 11. I learned through researching the Internet about Feramax 150 (non ionic), and take it since December 2012, and my levels rose from 7 to 18.

Have a good day.


My serum ferratin levels are approx 5 ATM, awaiting for an iron infusion.....have Anemia too.....also take B12 injections, so fed up of feeling weak, and tired....I'm from uk, GP is brill.....but I don't understand as to why my iron stores are sooooo low, far too low....wish I could get some answers as to why this keeps happening to me......anyone else have same constant problem? Thanks for Jill


I have reported this and another post by TiptonAyana as blatant advertising.

1 like

"For most of the people, Vitamin B12 patches work better than Vitamin B12 injections."

This is very wrong and has no evidence base


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