Pernicious Anaemia Society

Nitrous oxide and B12 def

Went today to see gastrolgist, he wants to do an endoscopy and colonoscopy (lucky, lucky me!). They offer sedation or laughing gas, I mentioned to the nurse doing all the talking that nitrous oxide could interfere with my already low vitamin B12, (thanks to the wealth of knowledge on here!) She looked at me as though I was talking a foreign language! "Hey doctor, have you ever heard of this?" He just looked perplexed (he did speak a foreign language) and shrugged. So I settled on the sedation, thanks very much.

As I booking the appointment the nurse came out telling that I was right about the nitrous oxide, thanked me for informing her but as I was only having a short procedure I would be okay.

Surely this would be alright if I didn't need B12 injections, and absorbing vits and iron as a 'normal' person, (hence the invasive procedures needed!) Am I right in thinking it could still damage my B12 levels even over a short period?

5 Replies

nitrous oxide doesn't change your B12 levels it just converts B12 to a form that the body can't use - making it inactive.

I don't think I would want to use nitrous oxide at all though the amounts of B12 washing around in blood are probably such that it's only going to have a small impact on the total amount of B12.


Would I still have B12 'washing around the blood' if I'm only on three monthly injections but probably need more, as I've still got pins and needles, shortness of breath and poor memory?


you can be deficient at cell level even tough you have lots in your blood though also possible if it is a while since you had an injection that your levels are low- how long since injection? have you ever had levels measured and doyou know how they vary after maintenance shots?


Had my loading doses between Christmas and New year, had my first maintenance injection on Monday. Levels before B12 were 152 (170-730). I went back to the doctors with evidence that I should be getting more before my first injection, he didn't read any and sent me off for vit D test :12 (50-250), Thyroid 'normal' and a referral to gastroenterology.

Feel tired still, but I have been trying to cut down on caffeine. Then started with pins and needles again yesterday, so I presume I need it more often, don't really know anymore. Feel like a hypochondriac at times...


you are not a hypochondriac.

you are being under treated - return of symptoms shows that - but that doesn't necessarily mean that B12 levels in your blood being low. Normal range is no guide at all if you have had a B12 shot.

unfortunately I don't have a magic bullet for over-coming attitude, lack of time and ignorance of GPs.

Important thing here is that you didn't use nitrous oxide


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