Kayexalate Dosing and Administration for Hyperkalemia
Recommended Dosage
For oral administration, give 15 to 60 grams daily in divided doses of 15 grams (four level teaspoons) one to four times daily, while for rectal administration, give 30 to 50 grams every six hours as a retention enema. 1
Oral Dosing Specifics
- Suspend each dose in 3 to 4 mL of liquid per gram of resin (water or syrup) 1
- Administer with the patient in an upright position 1
- One level teaspoon contains approximately 3.5 grams of sodium polystyrene sulfonate and 15 mEq of sodium 1
Rectal Dosing Specifics
- After an initial cleansing enema, insert a soft French 28 rubber tube approximately 20 cm into the rectum with the tip in the sigmoid colon 1
- Administer as a warm (body temperature) emulsion in 100 mL of aqueous vehicle and flush with 50 to 100 mL of fluid 1
- Retain the resin for as long as possible, then follow with a cleansing enema using a non-sodium containing solution with adequate volume (up to 2 liters) 1
Critical Timing and Separation Requirements
Administer Kayexalate at least 3 hours before or 3 hours after other oral medications; patients with gastroparesis require a 6-hour separation. 1
Preparation Guidelines
- Prepare suspension fresh and use within 24 hours 1
- Do not heat the resin as this alters its exchange properties 1
Mechanism and Expected Effect
- Kayexalate has a practical exchange ratio of approximately 1 mEq potassium per 1 gram of resin 2, 3
- The onset of action is delayed, typically taking several hours to days 4, 3
Critical Limitations and Contraindications
Kayexalate should NOT be used as emergency treatment for life-threatening hyperkalemia due to its delayed onset of action. 2, 4, 1
When NOT to Use Kayexalate
- Life-threatening hyperkalemia requiring emergency treatment 2, 4, 1
- Patients with hypersensitivity to polystyrene sulfonate resins 1
- Obstructive bowel disease 1
- Neonates with reduced gut motility 1
- Patients without normal bowel function 1
- Patients who have not had a bowel movement post-surgery 1
- Patients at risk for constipation or impaction (history of impaction, chronic constipation, inflammatory bowel disease, ischemic colitis, vascular intestinal atherosclerosis, previous bowel resection, or bowel obstruction) 1
For Acute Severe Hyperkalemia Instead Use:
Major Safety Concerns and Monitoring
Gastrointestinal Toxicity
Serious gastrointestinal adverse events including intestinal necrosis (some fatal), bleeding, ischemic colitis, and perforation have been reported, particularly when used with sorbitol. 2, 3, 1
- Concomitant administration with sorbitol is NOT recommended 2, 1
- Discontinue use in patients who develop constipation 1
- Cases of serpiginous ulcers in the stomach and terminal ileum have been reported 5
Electrolyte Disturbances
Monitor serum potassium, calcium, and magnesium during therapy because Kayexalate is not totally selective for potassium and can bind other cations. 2, 4, 3, 1
Sodium Overload
- Each 100 grams of powder contains 100 mg (4.3 mmol) of sodium, which may be problematic in patients with hypertension or fluid overload 2
- Severe hypernatremia has been reported in extremely low birth weight newborns 6
Special Population Considerations
Preterm Infants
- In preterm infants with nonoliguric hyperkalemia, salbutamol infusion is more effective with faster action and safer than Kayexalate 7
- Kayexalate use in this population has been associated with severe ventricular tachycardia, intestinal obstruction, and hypernatremia 6, 7
Preferred Alternatives for Chronic Management
For chronic hyperkalemia management, newer potassium binders like patiromer or sodium zirconium cyclosilicate (Lokelma) offer more predictable onset of action and potentially better safety profiles. 2, 3