1. Aschenbrenner, Diane S. MS, RN


* The labeling of sodium polystyrene sulfonate (Kayexalate), a drug used to treat significant hyperkalemia, has been revised to warn that the drug may bind to and render ineffective other oral drugs if given simultaneously.


* Only the oral form of sodium polystyrene sulfonate can produce these drug interactions.



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The labeling for the potassium-lowering agent sodium polystyrene sulfonate (Kayexalate) has been revised to include new information on potential drug interactions and recommendations for the timing of administration with other oral drugs.


Sodium polystyrene sulfonate is used to treat hyperkalemia, a condition in which the amount of potassium in the blood is too high. The drug works by binding to potassium in the intestines so that it may be removed from the body. When administered orally, sodium polystyrene sulfonate can also bind to other oral medications if they are taken concurrently. This would decrease the absorption and therefore the effectiveness of the other drugs.


Based on data from an in vitro study, the Food and Drug Administration (FDA) is now recommending that other oral drugs be taken three hours before or three hours after taking sodium polystyrene sulfonate. If the patient has gastroparesis, or another condition causing delayed emptying of food from the stomach into the small intestine, the spacing interval between medications should be six hours. This delay will allow for the absorption of sodium polystyrene sulfonate and prevent a drug interaction in the gastrointestinal tract. This FDA recommendation is only for patients taking the oral form of sodium polystyrene sulfonate, not the rectally administered form.


Nurses should adjust medication administration schedules for other oral drugs when patients require oral sodium polystyrene sulfonate.


To read the FDA Drug Safety Communication regarding sodium polystyrene sulfonate, go to