Should SPS (Kayexalate) Ever Be Used?

Sodium polystyrene sulfonate (SPS, Kayexalate) has been used for decades to help lower potassium levels and manage hyperkalemia. It does this by exchanging sodium ions for potassium ions in the gut (primarily the large intestine). The compound is then removed from the body out through the stool. It has some risks and controversy associated with its use that begs the question, should SPS ever be used?

From a polypharmacy perspective, I would strongly encourage you to review the medication list prior to considering an agent to reduce potassium levels. I’ve seen numerous cases where medications that can cause hyperkalemia have been overlooked, or not reported by patients. I’ve outlined 7 common medication causes of hyperkalemia in a previous post.

With regard to SPS, first and foremost, there is a significant adverse effect that can occur from the use of this medication. While not common, there has been a demonstrated risk of intestinal necrosis (great board exam question!). This risk appears more elevated when used with sorbitol. Patient risk factors for this adverse effect include GI disorders such as constipation, ileus, Ulcerative colitis, etc. Other potassium-binding medications do not seem to carry this same risk.

In addition to the possible serious adverse effect of intestinal necrosis, questions have been raised as to how effective the medication is at treating hyperkalemia. In this letter to the editor several years ago, serious questions have been raised as to how beneficial the medication is as well as the risk that may be encountered when using this medication.

Lastly, we have newer options available. Sodium zirconium cyclosilicate (SZC) and patiromer are relatively newer agents that can be used to help effectively lower potassium levels. We previously did a deep dive and provided some comparisons between cation exchangers in the management of hyperkalemia that you need to review.

The situations I can think of where SPS would be considered would be situations of drug shortages or limited access to some of the newer agents and other modalities to manage hyperkalemia.

What do you think, should SPS ever be used in favor of newer options?

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  1. EJB

    This is so interesting, I left the nursing homes in 2021 (as a nurse) and Kayexalate was still commonly used for incidents of hyperkalemia. I have been a nurse less than 10 years so It’s interesting to me how much things can change and how we are always learning new things. Frequently I’d see repeat instances of hyperkalemia in certain patients, especially those not on dialysis but with chronic kidney disease. So we know the kayexalate is not getting ro the root of the problem! And of course it’s very important to be aware of K+ increase from meds, especially spironolactone and BP meds – Are ACE inhibitors the biggest offenders?

  2. Emily

    Love all of these posts! And love that they come to my email – An easy reminder to read them when I get a chance. I have learned or been reminded of so many important things!

    • Eric Christianson

      Thanks for the kind words Emily!

  3. TK

    You are a board certified pharmacist, and such question should not be asked. You need to check guidelines where SPS is used. Maybe your posts should focus only on LTC and geriatrics. Better than dessiminating confused info for your followers. Thanks .

    • Eric Christianson

      Hi, I appreciate the comment and being challenged. I probably could’ve worded the title a little better such as “When should SPS be used?” – I’m far from perfect and try to do my research as much as possible and stay up to date. A student had asked me a while back when would you use Kayexalate given the GI risks and new agents available so I figured I’d look up what the latest info is on this topic. I acknowledge that SPS is frequently used in practice, but I don’t think it is a bad thing to ask the question if it is the right thing or should we be using other options. I neglected to share the articles that were critical of SPS due to not ideal evidence and GI risks use which you can find here from a few years ago:

      Also this one:

      It states the lack of large randomized controlled trials and the GI risk in the articles. I certainly could be missing something more recent, feel free to drop links to other articles that might provide clarity on this topic for the readers. – Best, Eric

  4. Evan Odean

    Hospital pharmacist here. SPS is still on order sets for hyperkalemia but in my opinion it shouldn’t be. Newer agents are preferred. I am yet to find an inpatient case where SPS is a good option.

    • Eric Christianson

      Thanks for the comment Evan! Hopefully costs will come down on the newer agents and more studies completed to give better clarity on the issue.


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Written By Eric Christianson

July 16, 2023

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