I have macrocytic anemia. My MCV for the past 7 years has hovered around 100. I had one good result of 93 and that was 3 months after getting loading shots of Cyanocobalamin when I was first diagnosed with B12 deficiency over a year ago. My doctor stopped my shots after that and I took only sublingual B12 since then (and folic acid) and my MCV is back up to 99. I could feel some of my B12 deficiency symptoms coming back so my doctor agreed to resuming shots once a month. The first one went OK, but after the second and third I felt like I was going to pass out and I ended up in the ER the second time. I felt weak in my legs, dizzy, and like I was going to faint. It was scary. I wondered afterwards if my potassium had suddenly dropped a few hours after the B12 shot. The first time it happened, I drank a sports drink at home and it resolved in a few hours. The second time I brought a sports drink with me to the ER, drank it there, and in the SIX hours I waited to be seen I started feeling better. My potassium was checked and was normal, but that was a few hours after I drank the Body Armor. MY MCV was still 99. I am actually feeling pretty well now, after a month of feeling crummy. My dilemma now is that when it comes time for my next shot, will the same thing happen? I talked to my doctor today and he said he never heard of Cyanocobalamin shots causing a drop in potassium. However, I have read about it in numerous places online. I’m afraid to taking my next shot in a few weeks (I self administer them now). What do you think?
B12 deficiency, macrocytosis, and pot... - Pernicious Anaemi...
B12 deficiency, macrocytosis, and potassium drop
Could it be your b.p dropping ??Is it possible to have the next one at your surgery to see if this is the case?
As you are bound to be apprehensive about the next one
I've only had a 'reaction ' twice that gave me similar to what you describe and took me to bed on my maintenance regime.
It turned out to be the brand of hydroxcobalamin so mustve been one of the preservatives.
In loading doses I was alot worse before better and very symptomatic .
Maybe a reaction to the surge of b12 so needed 🤔
All ideas .
Good you had your pottassium checked and it was okay
My bp was taken in the ER when this happened to me the second time and it was on the high side by the time I got there. I was thinking the same thing about having my next shot at my doctor’s office. I told my doctor that it had happened to me twice now. He said he didn’t know about any connection between the Cyanocobalamin shot and a drop in potassium. Perhaps he’ll research it before I need my next shot. He’s a very good doctor, and easy to talk to , so I feel comfortable asking him again if maybe I should take the shot in two separate doses or drink a sports drink before the shot. I’m sure he doesn’t want to have to deal with me passing out in his office! The more I research, the more I am finding that people with macrocytic anemia report having this issue. Thanks for your reply.
Your potassium was tested and okay .I'd think elsewhere 🤔
I eat a banana an hour before my b12, This helps me with the potassium
I eat a small banana with my breakfast every morning added to a nut, dried fruit, bran etc muesli as part of a mediteranean diet.
That should do it really then as far as potassium I would imagine. Coconut water is great for a banana break! Or tomato juice. x
Good idea. I was also thinking of loading up on Potassium before the shot to see if it prevents the “crash” feeling a few hours later. But I am on a break from bananas because after a banana ever day for a year and a half, I am honestly so sick of them! 😉
How could you understand that your potassium level decreased after vitb12 shot injection? By testing in lab? Did your doctor speak about possibility of anafilaxy shock or vasovagal syncope that some ones can develop it right after blood sight or injection? Because its not matter what is injecting.
Scientist, not medic.
MCV response is relatively slow, as it's the average size of your red cells, and red cells last around 120 days or so. Once you respond to something affecting your MCV [B12, Folate, Iron] then to see the full effect, it'll take four months. At 2 months it'll be half way there. The RDW [if you get it on your blood report] responds quite quickly, and reaches a maximum half way through the treatment cycle, and then falls once more once the response is complete.
If you're anaemic when treatment starts, then your potassium can certainly fall, but be very careful in supplementing potassium, as too much isn't good either.
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