What is the appropriate dose of kayexalate (polystyrene sulfonate) for a patient with hyperkalemia?

Kayexalate Dosing for Potassium 5.4 mEq/L

For a potassium level of 5.4 mEq/L, you can give 15-30 grams of kayexalate (sodium polystyrene sulfonate) orally once daily, with the standard dose being 15 grams (four level teaspoons) as the starting point. 1

Dosing Recommendations

The FDA-approved dosing for kayexalate is:

• Oral administration: 15-60 grams total daily dose, given as 15 grams (four level teaspoons) one to four times daily 1
• For mild hyperkalemia (K+ 5.0-5.9 mEq/L), 30 grams once daily has been studied and shown effective, reducing potassium by approximately 1.25 mEq/L over 7 days 2
• Each dose should be suspended in 3-4 mL of liquid per gram of resin 1

Expected Potassium Reduction

With kayexalate dosing for your patient's K+ of 5.4 mEq/L:

• A single 30-gram dose reduces potassium by approximately 0.7-0.8 mEq/L within 24 hours 3
• Daily 30-gram dosing over 7 days produces a mean reduction of 1.25 mEq/L 2
• The onset of action is delayed (not for emergency use), with measurable effects typically occurring 14-16 hours post-administration 3

Critical Safety Considerations

Do not use kayexalate with sorbitol - the combination has been associated with intestinal necrosis, some fatal, and other serious gastrointestinal adverse events including bleeding, ischemic colitis, and perforation 1

Additional precautions:

• Avoid in patients with constipation, inflammatory bowel disease, or history of bowel obstruction 1
• Monitor for hypokalemia, hypomagnesemia, and hypocalcemia during therapy 1
• Administer at least 3 hours before or after other oral medications (6 hours in gastroparesis) 1

Alternative Consideration

At K+ 5.4 mEq/L, strongly consider using newer potassium binders instead of kayexalate, particularly if the patient is on RAAS inhibitor therapy that you want to maintain. Sodium zirconium cyclosilicate (Lokelma) 10 grams three times daily for 48 hours would reduce potassium by approximately 1.1 mEq/L with faster onset (1 hour) and superior safety profile 4. The newer binders enable optimization of cardioprotective RAAS inhibitor therapy rather than requiring dose reduction 5.

Monitoring Protocol

After initiating kayexalate:

• Recheck potassium within 24 hours to assess response 1
• Monitor serum calcium and magnesium levels 1
• Ensure adequate bowel function and watch for constipation 1
• If on RAAS inhibitors, do not discontinue them; instead manage hyperkalemia with binders to maintain cardioprotective therapy 5