Wondering how fast could your B12 levels go down with someone who has a B12 deficiency?

They can go down pretty quickly and they can be raised pretty quickly as well with a shot. Some people are more sensitive than others and react quickly in the energy department to a B12 shot. It's also something you can easily give her rather than having to take her in for it all the time. Her doctors nurse should be able to train you very quickly. There is also B12 available in sublingual form, it isn't as effective and may not be the same make up (injection being better often) but if she can keep something under her tongue it might be worth picking some up to give her until you can get her back in a schedule with the injections.

Her b12 order should be in place while in any facility.

Surprisingly fast. My dad was unable to get his B12 shot for two months while caretaking my mother during a decline she went through right before entering AL.
My dad was feeling very weak, tired and was quite IRRITABLE and snappish. I didn’t realize he hadn’t been able to leave my mother to even go get his shot!

But YES, elders are very sensitive about missing their B12 and it can have noticeable effects on their mental function and their moods.

It can drop quickly naturally and quicker when reliant on supplement.

Every 30 days.

Partly depends on why she is deficient and what kind of shot she is getting. In the U.K. people with pernicious anaemia get an injection everym3months and levels are generally fine with that. However some people need more and there is some evidence that serum levels do not adequately reflect the effect. ie. one might have normal levels but possibly have a higher requirement or lower sensitivity. It’s not clear. However, you cannot really overdose on B12 (only A, D, E and K vitamins) so I agree that if it’s difficult to get her in for a shot then start oral/sublingual. It’s better than nothing. And it’s useful to be able to do it at home. However, it is also useful to have a general screen. There are other vitamins and minerals which can cause fatigue when your levels are low eg iron, folate and Vit D.

Her fatigue and difficulty with PT may be worse if she is B12 deficient (is she? Has anyone checked?); but are they not more likely related to whatever took her to hospital twice and has led to her evaluation for hospice care?

Still. It's a simple test and a simple px. Get the rehab team to run and find out!

Insist on her getting the B12 shots! If she got them regularly, she must be deficient by now. Fatigue is a symptom of the deficiency.
They'll call in a doctor - but you want that too.

Also, I forgot to add that the effect was almost immediate. I felt like a new person. I hope your loved one can get back on it soon, however you do it. Sometimes meds etc get lost, that is why you have to be your own advocate.

My Mother and I both had low vit B and D. So, the Dr said to take supplements. B12. It kept her levels normal. And yes, low B12 will make you very tired.