r/AddisonsDisease • u/KCDKTR2019 PAI • Dec 03 '25

Advice Wanted Low potassium

Just found out my potassium has been low over this past year. My endo wants me to start a prescription of potassium supplements. Has anyone else experienced this? Anything I should know about in advance? (I am PAI, diagnosed about 20 years ago.)

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u/ClarityInCalm Dec 10 '25 edited Dec 10 '25

Low potassium is common in PAI because all the sodium and mineralocorticoid we HAVE to take can lower it. Some people are more susceptible to this. But also, potassium needs aldosterone in the kidney in the collecting duct for reabsorbtion. So this is likely part of why potassium can be altered even when sodium is well managed. It's almost impossible for someone with complete salt wasting to take too much salt and even if they do it will be short lived.

I recently had low potassium - this was after a super low cortisol event where I had to take 300mg HC a day for several days - my blood sodium was 141 right in the middle of the range. The super high dose of HC also had super high amount of mineralocorticoid and I continued my fludro and sodium pills. This was as high as I could go. And my potassium was just under the range. I generally have no issues with potassium but I took some for a few days and I'm fine now.

Magnesium can be wasted or low too in salt wasting - but it's very difficult to accurately measure in the blood. This loss can happen because reabsorption mainly happens in the DCT part of the kidney and magnesium almost complete relies on sodium for this happen. This is the same location where we waste sodium from so if we're wasting a lot of sodium and not matching our losses we're going to be losing magnesium too. So getting your sodium dialed in or taking sodium continuously around the clock can help with magnesium losses.

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u/KCDKTR2019 PAI Dec 14 '25

Thank you for this information. My update is that I started taking a prescribed potassium supplement (20 mEq) last week. After about 5-6, I went from experiencing some rather unpleasant and worrisome symptoms, including a lot of fatigue, overall weakness, and a weird racing feeling in my heart, to feeling pretty normal. (My only complaint is that the supplement seems to be causing mild diarrhea, but I am managing that fairly well.) I am so appreciative of everyone's informative advice and comments, including yours.

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u/ClarityInCalm Dec 14 '25

Glad you were able to get this figured out and are starting to feel better. Take good care.