What is the recommended dose of Kayexalate (sodium polystyrene sulfonate) for treating hyperkalemia?

Recommended Dosage of Kayexalate (Sodium Polystyrene Sulfonate) for Hyperkalemia

The recommended dose of Kayexalate (sodium polystyrene sulfonate) for treating hyperkalemia is 15-60 g orally per day, administered as 15 g one to four times daily, or 30-50 g rectally every six hours. 1

Oral Administration

• The average total daily adult dose is 15-60 g, typically given as 15 g (four level teaspoons) one to four times daily 1
• Oral suspension should be prepared by suspending each dose in a small quantity of water or syrup (approximately 3-4 mL of liquid per gram of resin) 1
• Administer with the patient in an upright position to reduce risk of aspiration 1

Rectal Administration

• The average adult rectal dose is 30-50 g every six hours 1
• Administer as a warm (body temperature) emulsion in 100 mL of aqueous vehicle and flush with 50-100 mL of fluid 1
• Follow administration with a cleansing enema using a non-sodium containing solution (up to 2 liters) 1

Important Clinical Considerations

Timing and Onset of Action

• Kayexalate should NOT be used as emergency treatment for life-threatening hyperkalemia due to its delayed onset of action (several hours to days) 1, 2
• For acute, severe hyperkalemia, use more rapid-acting treatments first (calcium, insulin/glucose, nebulized albuterol) 2
• Administer Kayexalate at least 3 hours before or 3 hours after other oral medications (patients with gastroparesis may require a 6-hour separation) 1

Efficacy

• Serum potassium reduction is dose-dependent:
  • 15 g oral dose: approximately 0.39 mEq/L reduction 3
  • 30 g oral dose: approximately 0.69 mEq/L reduction 3
  • 60 g oral dose: approximately 0.91 mEq/L reduction 3
  • 30 g rectal dose: approximately 0.22 mEq/L reduction 3

Monitoring

• Regular monitoring of serum potassium is essential during therapy as severe hypokalemia may occur 1
• Monitor calcium and magnesium levels, as Kayexalate is not totally selective for potassium and can bind other cations 1, 2
• Monitor for fluid overload in patients sensitive to sodium intake (heart failure, hypertension, edema), as each 15 g dose contains 1,500 mg (60 mEq) of sodium 1

Safety Concerns and Contraindications

Contraindications

• Hypersensitivity to polystyrene sulfonate resins 1
• Obstructive bowel disease 1
• Neonates with reduced gut motility 1

Major Adverse Effects

• Serious gastrointestinal adverse events including intestinal necrosis (some fatal), bleeding, ischemic colitis, and perforation have been reported 1, 4
• Risk factors for GI adverse events include prematurity, history of intestinal disease or surgery, hypovolemia, renal insufficiency, and failure 1
• Electrolyte disturbances including hypokalemia, hypocalcemia, and hypomagnesemia 2

Precautions

• Avoid use in patients at risk for developing constipation or impaction (including those with history of impaction, chronic constipation, inflammatory bowel disease, ischemic colitis, vascular intestinal atherosclerosis, previous bowel resection, or bowel obstruction) 1
• Discontinue use in patients who develop constipation 1
• Concomitant administration with sorbitol is not recommended due to increased risk of intestinal necrosis 1, 4

Alternative Potassium Binders

• For chronic hyperkalemia management, newer agents such as patiromer or sodium zirconium cyclosilicate may be considered, especially in patients who don't respond to Kayexalate 2
• These newer agents have more predictable onset of action and potentially better safety profiles 2