Extremely basic K supplementation question

[EminenceBasedMedicine]

I'm covering at an eating disorder service at the moment. There's a bunch of patients that get frequent potassium checks, and often return values in the low 3s and sometimes high 2s particularly after a bout of purging.

Practice here seems to be to supplement with between 1-4 tabs of KCl (8mmol K each), then stop when K returns to the normal range. Often the same people become hypokalemic over and over again.

My question is: can't we just leave them on supplementation for a few weeks? Is there any significant risk of hyperkalemia in an otherwise healthy young adult?
I can't find much info online about this and it's been a long time since I've studied it. But my understanding is K is predominantly intracellular, is tightly controlled* (assuming normal renal function), and a normal blood level doesn't preclude a whole-body deficit.

*Eating a few bananas would surely kill you if this wasn't the case?

---

Members don't see this ad.

 

[NewYorkDoctors]

Oral KCl is proemetic. It’s the esophagitis that may occur . Kind of defeats the purpose for a bulimic .

Bananas may be safer

Tomatoes too for that matter .

Plus hypokalemia can serve as a sign of occult sneaks as well .

 

[Crayola227]

Everything is more expensive in the hospital. As pointed out the fewer pills you give a patient the better.

 

[EminenceBasedMedicine]

If these patients could so easily eat a few bananas, they wouldn't require inpatient treatment for their anorexia nervosa...

The K used is typically modified release

 

[aafisahar]

if you have normal kidneys/heart, you can tolerate daily potassium repletion within reason.

 

[Crayola227]

if you write to replete someone beyond when their K nomalizes per labs, how is that going to look if they end up hyperkalemic with a bad outcome?

 

[EminenceBasedMedicine]

But how are they going to become hyperkalemic on oral supplementation equivalent to a banana or less? I want to know the mechanism

 

[geripalgal]

Dont forget to replete Mag!
Agree with the cost issue, but if you have needed on average 1-4 pills per day over the last few days, then having 1 pill scheduled daily and the rest as needed makes sense to me - once she stops needing the extra pills you can cut back on the scheduled one.


Also, from my understanding its not easy to beome hyperkalemic on oral meds (but very easy on parenteral options) due to how its absorbed. Of course in someone with an eating disorder, everything is off...

Whats the cost of the BMP vs the kcl tab?

 

[EminenceBasedMedicine]

Thanks for your responses.
The KCl costs [edit: the government] 2 cents a tab thanks to the glories of socialised healthcare

 

[bobsmith]

Apparently I can't post links, but if you search pubmed for "Early and late adjustment to potassium loading in humans" by Rabelink TJ, Koomans HA, et al., it's a study that gave healthy adults 400mmol/day of K orally (over 4 meals) x3 weeks after an initial control period where they only got ~100mmol/day of K in their meals.

Long story short, all the subjects were fine and nobody got hyperkalemic because the kidneys (+ renin/aldosterone system) are super smart and adapt in both the short and long-term.

It's possible that the renin/aldosterone system in your patients is altered due to their disorder and underlying metabolic abnormalities, but realistically, your patients would also most likely be fine if you put them on a small amount of standing potassium supplementation.

Agree with above poster, however, that hypokalemia can be a sign of occult behavior, so masking that would not be ideal.

 

[NewYorkDoctors]

CLINJASN | Mobile

Dont even need an uptodate log in .

 

[phltz]

If people have healthy kidneys, there is little risk of causing hyperkalemia with reasonable standing supplementation. Here's a study giving people 96mEq daily of KCl vs. K citrate as a treatment for hypertension, for example <https://www.ahajournals.org/doi/abs/10.1161/01.HYP.0000158264.36590.19>. Here's a study giving elderly people with low bone density 60mEq daily of K citrate to improve calcium balance <Effect of Potassium Citrate on Bone Density, Microarchitecture, and Fracture Risk in Healthy Older Adults without Osteoporosis: A Randomized Controlled Trial | The Journal of Clinical Endocrinology & Metabolism | Oxford Academic>. According to uptodate, K citrate can be used up to 100mEq a day for hypocitrauric stones with recommended monitoring Q4months. All of which is to say that having standing potassium supplementation should generally be safe for people with normal renal function and no other medications or medical problems that would be likely to cause hyperkalemia.