Interestingly after ten years of having what i would describe loosely as 'zombie POTS' where i just felt terrible OI and dizziness, fatigue etc which responded quite well to midodrine and florinef, last year my POTS did a complete 180 degrees and hit me with the most intense hyperadrenergia ive ever experienced in 18 years of POTS on and off. It went on for 6 and then 15 days of solid daily BPs of 180/110 and HRs of 140 and it was utterly horrendous.
I was climbing the walls and actually felt like I was mentally losing it from the constant feeling of panic. And I have absolutely no idea why it went that way after over a decade of a fairly stable presentation with relapses and remissions.
Pretty much threw out all of the past research I had read about the causes of POTS - made me start to think it may be more of a spectrum or something; or perhaps sometimes it just swings the other way for what ever reason.
So now Im on clonidine and its been very helpful for me although it promotes OI but I kind of prefer dizziness to feeling so wired I cannot sleep and startle all day at birds etc.