Pernicious Anaemia Society
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Is 10,000mcg of hydroxocobalamin weekly too much?

It is a long story as to how I am on this dose but it is done within the health system though I have to purchase the B12 via a private prescription as only the cyanocobalamin is available on a normal prescription.

When I went to gather information as to what was available before speaking to my doctor, the pharmacist was obviously low on knowledge as his first remark was that all the three cobalamines that I queried were 'the same'. After spending time looking for a point of purchase for the hydroxo he informed me that yes he had found one but needed a doctors prescription to order it. Told him no problem but to save time when I came back with the order, to please write down the relevant information. I went off to the doctors, gave him my arguments as to why I would like to change from the cyano (once a month) to hydrox (once a week) and we came to an understanding. After 2/3 weekly injections I was glancing through the prospectus and realised that the strength was 10,000 mcg.

My dilema is what to do. I have decided to use up the 10 injections (still have 5 left) then do I go to the doc and casually ask him if there is a lower dosage or just keep taking them. If I use the first option I may lose his trust as I do the research then go back to him. He is a replacement of the original doctor who fitted well into the category that we all know and fight, and I value his open mindedness, interest and trust. I certainly do not want to lose this. I know about the non toxicity and also the potential lowering of potassium.. I take folic acid, iron and copper.

I cannot say the peripheral nerve damaged has improved but it feels different and my walk feels more 'normal' so I am very optimistic and consider the treatment well worth sticking to. I have had no adverse effects - its just the numbers that I am not totally comfortable with.

I appreciate that it is 'opinions' that I am asking for but it seems to me that there are a lot of well read, knowledgeable members out there so I would very much appreciate your time.

15 Replies

oh gosh .... I wouldn't rock the gp boat.

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Truly a girl after my own heart. Keep smiling.

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Just don't say anything...

Early signs are good. :-)

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Hi Hillwomen, what I forgot to mention is that the plan is to have the weekly injections for six months (my nerve damage is quite bad) so do you think the dosage acceptable for this length of time? I accept that it is not toxic but the dosage is high and I have spent hours searching for anything that even touched on this but without success. I love the idea but just find myself being a bit wary.

Thank you for replying and I wish you all the best.


Sorry for not replying sooner. Just had a look at Gambit's comment below - you need to check the strength, but if it is working for you then you really do need to continue at this dosage and treatment rate until there is no further improvement. With neuro damage this is especially important, and something I wish I'd known a long time ago.

Good luck.


Thank you Hillwoman. Again thank you (such small words to contain the feelings they represent)

I feel calmer and safer especially after your remarks regarding the neuro damage. Sounds like you have been there! I do hope that you are still improving.

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Are you sure that you are looking at the amount in a phial rather than half of the measure of the concentration? the concentration would be an amount in mcg followed by a volume in litres of millilitres. eg 10,000mcg in 10ml as the the concentration would be 1000 mcg per ml so you would need to take 1 ml to get 1000mcg=1mg.

In any case - if they seem to be working for you I'd stick with it.


Thank you Gambit62 for your time and opinion.

The prospectus reads "An ampoule of 2 ml contains 10,000 microgrammes of hydroxocobalamin. An ampoule of 1 ml contains 5,000 microgrammes of hydroxocobalamin".

It also states that the box (that I have) contains "10 ampoules of 2 ml".

I am in Spain but assure you that the translation above is correct and I cannot see how I have misunderstood it. However, I would not be totally shocked if you said that I had misinterpretated it.

I have noticed your many replies to other members of this forum and hold you in high regard so do take on board your opinion to stick with this strength.

Many Thanks


No, looks like your interpretation is correct - so back to if it is working continue to go with it.


Since hydroxocobalamin stays in the body longer than cyano, you may get the same benefit for taking 1 ml of hydroxocobalamin per month as you would get taking 1 ml of cyano a week.

I've taken both and found the UK regime of 1 ml of hydroxocobalamin every three months was not sufficient. My GP moved me to an injection every 2 months and then, after more begging, to once a month.

When I moved to the USA, the regime was monthly injections 1 ml of cyanocobalamin. This wasn't sufficient and my new GP moved me to an injection every two weeks. I started self injecting and he moved me to weekly 1 ml of cyano. ( I actually take 0.5 ml on Monday and 0.5 on Thursday ) and things are pretty stable.

On stress filled days, I take supplemental methyl cobalamin sublinguals 2x 5mg under the tongue and it lasts 5 hours.

Start a logbook and monitor the timing of your symptoms. Some symptoms occur within 48 hours after the injection. The more severe these are, the lower you were before the injection. Share this logbook and symptoms with your GP, especially the neurological ones. He may treat you like a hypochondriac at first but after he/she realizes you are self monitoring, he will begin to trust you.

I get annual blood tests and expect the B12 levels to be off the top of the scale >1500 pg/ml.

I also take a daily centrum multivitamin for men, 3.2 mg of folic acid, 100 mg of B6 for nerve repair, 500 mg of TMG, and a D3 gelcap.

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on average people retain hydroxo twice as long as cyano-cobalamin but there is a lot of variation and significant numbers of people actually retain cyano longer than hydroxo.

Unfortunately it would appear that most of the medical profession and certainly the majority of bureaucrats around it do not really understand statistics and statistical variation and the dangers of applying what is in this case a rather sweeping generalisation to actual patients.

Even going on the averages 3 monthly shots for hydroxo has no scientific justification


Many thanks pvanderaa and I am glad that you have reached a dosage that you are happy with (even though you had to move to America to attain it)

Cyanocobolamin is the normal route here in Spain, hydroxo is available through private prescription and methyl is just not available (as provided by the pharmacist). I was on cyano, once a month, 1,000 mcg but it was having no affect. My damage was getting worse and my B12 numbers were dropping so after a lot of research and the "Could it be you B12" book plus the change of doctor at my surgery gave me the push to start fighting, yet again.

I found this forum quite recently and find it quite inspirational though I have been reduced to tears at the fight some have on their hands.

I think I may be 'ranting' so will wish you good luck and good health.


Ranting is normal. Please carry on as it is therapeutic. The worry and anxiety are actual symptoms of B12D.

The logbook really provides a tangible way to gain back some control. Then you can relax and make good decisions based on your symptoms.

You kind of become your own Guinea pig or lab rat as you experiment to find out what works and what doesn't work for you.

Track all your medications in the logbook too.


The move to the USA was work related. I had to go through the whole process with a new GP to get sufficient B12.

The logbook really was a successful tool in convincing both GPs that the symptoms were real and I actually needed more B12.

I found during a trip to Saudi Arabia, I could get methyl B12 over the counter. Have you looked at what is available in Morocco?

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I am keeping a log book though more for me than a tool of persuasion, but of course it will be there if necessary.

If I have a choice of buying from a farmacia here or via the internet, then for me, I would always go for the farmacia. I do however much appreciate your time and suggestions.

Many thanks again and good luck.


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