Need help with resources to show doc

[Mcpowell]

Can anyone point me in the direction of research/journal articles that explain potassium dropping with use of B12? I went to my doc today and she had never heard of it and acted like I was crazy. Thanks in advance!

[Foggyme Administrator]

Hi Mcpowell. A fall in pottsssium is usually only problematic in those who also present with macrocytic anaemia (large red blood cells). And not everybody who has B12 deficiency has macrocytic anaemia as a symptom of that deficiency.

Where macrocytic anaemia is present, potassium gets used up more quickly as the red blood cells repair - once the initial repair process is completed, extra potassium is no longer required and the potassium 'requirement' therefore reverts to normal.

So, in this sense, problems with potsssium are related to the underlying macrocytic anaemia (because the large macrocytic red blood cells use extra potassium in the repair process) rather than to the B12 injections themselves.

GP's should be aware of this reaction as a potential when macrocytosis is present and B12 therapy is commenced.

Here's something to show your GP (extracted from page 6 PDF version, page 501guideline page referencethe - BSCH 'Guidelines for the Diagnosis and Treatment of Cobalamin and Folate Deficiencies'):

Patients presenting with severe anaemia may develop a transient hypokalaemia following treatment, the clinical sig- nificance of which is unknown (Carmel, 1988), and potas- sium replacement therapy may be considered'

Here's a link to the full guidelines (your GP may be interested to read them):

onlinelibrary.wiley.com/doi...

Hope this helps.

👍

[Mcpowell in reply to Foggyme]

Thank you! I’m trying to figure out why my potassium tanks whenever I take even small doses of sublingual HydroxyB12. I actually have lower mcv, right at the borderline between low and normal. However, I also get very thirsty and pee a lot more when I take b12, so perhaps it had nothing to do with mcv at all.

[Foggyme Administrator in reply to Mcpowell]

Hi McPowell.

Low MCV is associated with iron deficiency anaemia and produces smaller (microcytic) red blood cells. If these smaller red blood cells are present, they can 'mask' the presence of larger red blood cells associated with macrocytic anaemia (because the cells are made smaller)...if you see what I mean.

A way to determine whether macrocytic is present in those who have iron deficiency anaemia (evidenced by low mcv / microcytic red blood cells) is via a blood test called a blood film. This test stains all the red blood cells so that they can be examined under a microscope and checked for a mixture of both microcytic and macrocytic red blood cells (because it’s possible to have both at the same time.

It's also worth noting that all elements of the FBC have to be read over and against each other to get a full picture of haematological status. Here's a link to information that might help:

labtestsonline.org.uk/tests...

If an recall, you were put on potsssium tablets following your hospital treatment for low potassium...so might be worth upping you B12 whilst taking the extra postassium because if B12 is causing an extra potassium requirement, then you're already having this so the issue of 'tanking' B12 shouldn’t occur. And the potential requirement for additional potassium only happens in the initial stages of B12 treatment, so you'd have this covered).

Good luck 👍