Kayexalate Dosing and Administration for Hyperkalemia
Critical Limitation
Kayexalate (sodium polystyrene sulfonate) should NOT be used as emergency treatment for life-threatening hyperkalemia due to its delayed onset of action (several hours to days). 1, 2
Recommended Dosage
Oral Administration
- Standard dose: 15 g orally, administered 1 to 4 times daily (total daily dose 15-60 g) 2
- One level teaspoon contains approximately 3.5 g of sodium polystyrene sulfonate (15 g = four level teaspoons) 2
- In a randomized controlled trial, 30 g daily reduced serum potassium by 1.04 mEq/L more than placebo over 7 days in patients with mild hyperkalemia (K+ 5.0-5.9 mEq/L) 3, 4
Rectal Administration
- Standard dose: 30-50 g every 6 hours as retention enema 2
- Administer as warm (body temperature) emulsion in 100 mL aqueous vehicle 2
- Insert soft, large-bore (French 28) rubber tube approximately 20 cm into rectum with tip in sigmoid colon 2
- Retain as long as possible, then follow with cleansing enema using non-sodium containing solution (up to 2 liters) 2
Preparation Instructions
Oral Suspension
- Suspend each dose in 3-4 mL of liquid per gram of resin (water or syrup) 2
- Prepare suspension fresh and use within 24 hours 2
- Do NOT heat the resin as this alters exchange properties 2
- Administer with patient in upright position 2
Drug Interaction Timing
- Administer at least 3 hours before or 3 hours after other oral medications 2
- Patients with gastroparesis may require 6-hour separation 2
Critical Safety Warnings
Gastrointestinal Toxicity
- Cases of intestinal necrosis (some fatal), bleeding, ischemic colitis, and perforation have been reported 2
- Concomitant administration with sorbitol is NOT recommended due to increased risk 2, 5
- Use only in patients with normal bowel function 2
- Avoid in patients without postoperative bowel movement or those at risk for constipation/impaction 2
- Discontinue if constipation develops 2
Electrolyte Disturbances
- Monitor serum potassium during therapy as severe hypokalemia may occur 1, 2
- Sodium polystyrene sulfonate is not selective for potassium and can bind calcium and magnesium 6, 2
- Monitor calcium and magnesium levels during treatment 1, 2
Sodium Overload
- Each 15 g dose contains 1,500 mg (60 mEq) of sodium 2
- Monitor patients with heart failure, hypertension, or edema for fluid overload 2
- Adjust other sodium sources as needed 2
When to Use Alternative Treatments
Acute Severe Hyperkalemia
- For life-threatening hyperkalemia, use rapid-acting treatments first: calcium, insulin/glucose, or nebulized albuterol 1, 6
- The American Heart Association and American College of Cardiology recommend against Kayexalate for emergency treatment 1, 6
Chronic Hyperkalemia Management
- Consider newer potassium binders (patiromer or sodium zirconium cyclosilicate) for more predictable onset and potentially better safety profiles 6
- These agents demonstrated significant potassium reduction in clinical trials with better tolerability 3
Common Pitfalls to Avoid
- Do not use in neonates with reduced gut motility (contraindicated) 2
- Do not combine with sorbitol due to increased intestinal necrosis risk 2, 5
- Do not expect rapid potassium reduction—onset takes hours to days 1, 2
- Do not use in patients with obstructive bowel disease (contraindicated) 2
- Do not overlook the high sodium content when managing fluid-sensitive patients 2