What is the recommended dose and treatment approach for hyperkalemia using Kionex (sodium polystyrene sulfonate)?

Recommended Dosing and Treatment Approach for Hyperkalemia Using Kionex (Sodium Polystyrene Sulfonate)

For non-emergency hyperkalemia treatment, the recommended dose of Kionex (sodium polystyrene sulfonate) is 15 g orally 1-4 times daily or 30-50 g rectally 1-2 times daily, with careful monitoring for gastrointestinal adverse effects. 1, 2

Dosing Guidelines

Oral Administration:

• Standard dosing: 15-60 g total daily dose, divided as 15 g (four level teaspoons) 1-4 times daily 2
• Preparation: Suspend each dose in 3-4 mL of water or syrup per gram of resin (approximately 45-60 mL liquid for a 15 g dose) 2
• Administration timing: Give at least 3 hours before or 3 hours after other oral medications (6 hours for patients with gastroparesis) 2
• Patient position: Administer with patient in upright position 2

Rectal Administration:

• Standard dosing: 30-50 g every 6 hours 2
• Preparation:
  • Administer as a warm (body temperature) emulsion in 100 mL of aqueous vehicle
  • Flush with 50-100 mL of fluid
  • Follow with a cleansing enema using non-sodium containing solution (up to 2 liters) 2
• Administration technique:
  • Initial cleansing enema first
  • Insert a soft, large size (French 28) rubber tube into rectum for about 20 cm
  • Ensure tip is well into sigmoid colon and tape in place
  • Agitate emulsion gently during administration
  • Retain resin for as long as possible 2

Important Clinical Considerations

Efficacy and Onset of Action

• Onset: Variable, typically several hours 1
• Not for emergency use: Should not be used for life-threatening hyperkalemia due to delayed onset of action 2
• Efficacy data: In a randomized clinical trial, SPS reduced serum potassium by 1.25 mEq/L compared to 0.21 mEq/L with placebo over 7 days 1, 3

Safety Considerations

• Contraindications:

  • Hypersensitivity to polystyrene sulfonate resins
  • Obstructive bowel disease
  • Neonates with reduced gut motility 2

• Major warnings:

  • Risk of intestinal necrosis (some fatal cases reported)
  • Other serious GI adverse events: bleeding, ischemic colitis, perforation 2
  • Avoid in patients with constipation or at risk for impaction 2

• Common adverse effects:

  • GI disorders: constipation, diarrhea, nausea, vomiting, gastric irritation
  • Electrolyte disturbances: hypomagnesemia, hypokalemia, hypocalcemia, systemic alkalosis 1

Monitoring

• Electrolytes: Regular monitoring of serum potassium, calcium, and magnesium levels
• Bowel function: Discontinue if constipation develops 2
• ECG monitoring: For moderate to severe hyperkalemia (>6.5 mmol/L) 4

Treatment Algorithm for Hyperkalemia

1. Assess severity of hyperkalemia:

   • Mild: 5.0-5.5 mEq/L
   • Moderate: 5.6-6.5 mEq/L
   • Severe: >6.5 mEq/L 1, 4

2. For severe or symptomatic hyperkalemia (>6.5 mEq/L):

   • First stabilize cardiac membrane with calcium gluconate 10% solution (15-30 mL IV)
   • Shift potassium intracellularly with insulin/glucose (10 units regular insulin with 50 mL of 25% dextrose)
   • Only after acute treatment, consider Kionex for ongoing management 4

3. For mild to moderate hyperkalemia (5.0-6.5 mEq/L):

   • Initiate Kionex at 15 g orally 1-2 times daily
   • Adjust dose based on potassium levels and response
   • Consider alternative newer potassium binders (patiromer or sodium zirconium cyclosilicate) if available, which have fewer GI side effects 1, 4

4. For maintenance therapy:

   • Low-dose daily Kionex can be effective for secondary prevention of hyperkalemia in patients on RAAS inhibitors 5
   • Titrate dose based on regular potassium monitoring

Comparative Considerations

Kionex has several limitations compared to newer agents:

• Selectivity: Nonselective binding (also binds calcium and magnesium)
• Sodium content: 1500 mg sodium per 15 g dose (caution in heart failure, hypertension)
• Sorbitol content: 20,000 mg per 15 g dose (contributes to GI side effects)
• Safety profile: Higher risk of serious GI adverse events compared to newer agents 1, 4

When possible, consider newer potassium binders like patiromer or sodium zirconium cyclosilicate, which have better safety profiles and more predictable potassium-lowering effects 1, 4.