Cation-exchange resin used for hyperkalemia

• A. Kayexalate
• B. Sodium formaldehyde sulfoxylate
• C. Sodium polystyrene sulfonate
• D. A and B

Answer: (C)

Cation-exchange resins used for hyperkalemia work by binding potassium in the gut and exchanging it for another cation, effectively pulling potassium out of the body via the intestines. Sodium polystyrene sulfonate does this in the colon, swapping potassium for sodium, which lowers serum potassium over several hours. Kayexalate is simply the brand name for the same compound, so it shares the same mechanism. Sodium formaldehyde sulfoxylate isn’t a resin used for treating hyperkalemia, so it wouldn’t be chosen. In short, the resin that reduces potassium in the gut through this exchange process is sodium polystyrene sulfonate. It’s important to note it isn’t for rapid stabilization in a life-threatening hyperkalemia situation and should be used with awareness of potential GI side effects and interactions with other medications.