Hi
@Gingergrrl - actually, I haven't had much of a problem with POTS, certainly nothing like you or others on this board. I started taking thiamine because of crashing - PEM. For me at least PEM involves a build-up of lactic acid way out of proportion to energy expended - it causes achiness and severe fatigue, and I know my crash is over when the achiness goes away. So I recently read that thiamine can help resolve lactic acidosis, which is not the same thing as PEM, but I'm sure they're related because of the issue with lactic acid. And then I read about thiamine being so important with energy production. I may have stated all this elsewhere. So recently - within the last 2 months I think - I re-started taking B1 in smaller doses than before. First I took I think 100 mg. and then cut back to about 30 - about 1/4 of a 100 mg. capsules.
Initially it really boosted my energy a lot (unlike when I tried 400 mg. quite awhile ago) and then after a couple of days I started going downhill, extra fatigue, not feeling well. It's a long story but I'm now theorizing that it was causing hypophosphatemia (low phosphorus). I got this idea from first reading Freddd's post about refeeding syndrome. (
http://forums.phoenixrising.me/inde...es-to-healing-via-induced-deficiencies.41605/) and then doing a little more research on my own about refeeding syndrome:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440847/:
The hallmark biochemical feature of refeeding syndrome is hypophosphataemia.
I was pretty sure my extra fatigue was not due to low potassium as I was already taking supplemental potassium and when I upped it, my symptoms did not abate.
So I'm currently working on the idea that induced-low phosphorus was causing my difficulty with taking B1, and am drinking lots of kefir (which is high in phosphorus), but also today I found a source for taking phosphate as a supplement. I understand you have to be careful with supplementing with phosphate, and am seeing my CFS doctor this week and will run it all by him.
So I know none of this ostensibly has anything to do with POTS, your initial question, and I apologize for the sidetrack, but it's what I've been dealing with.
But in my reading about thiamine - which is so crucial for so many processes - I came across its relationship with POTS and did my post linked above, hoping it might help someone.
Interestingly, I came across this article regarding a connection between hypophosphatemia and POTS:
http://www.ncbi.nlm.nih.gov/pubmed/6706445
I also came across this reference, which talks about both hypophosphatemia and thiamine (separately):
https://books.google.com/books?id=w...INTAD#v=onepage&q=thiamine phosphorus&f=false
It mentions cardiac issues, which sound suspiciously like some of my abnormal results from impedance cardiography testing several years ago, which I'm also going to run by my doctor.
When my sister had FQ toxicity, it was several years ago, before I knew anything about thiamine etc. And she did not get sick like you, though she did have tendon damage and I think had a couple of surgeries. But I will be seeing her in about 6 weeks and will talk to her about thiamine then. Thanks for the reminder!
So I'm sorry this reply is so long in answer to your questions, but nothing is simple with this DD!
Anyways, initially