Kayexalate

Aka: Kayexalate, Cation-Exchange Resin, Sodium Polystyrene Sulfonate, Potassium Binding Agents

1. See Also
   1. Hyperkalemia Management
2. Indications
   1. Symptomatic Hyperkalemia
3. Preparations
   1. Sodium Polystyrene Sulfonate (Kayexalate)
      1. Older agent, developed in the 1960s, and described on this page
   2. Newer Potassium binders (see linked pages)
      1. Patiromer (Veltassa)
      2. Zirconium Cyclosillicate (Lokelma)
4. Mechanism: Kayexalate
   1. Cation exchange resin that releases Sodium and binds Potassium
   2. Each gram of Kayexalate contains a resin that binds 1 meq/L Potassium
   3. Sorbitol was added to decrease Constipation associated with the resin
      1. Sorbitol reduces Potassium as much (or as little) as the binding resin
5. Precautions: Kayexalate
   1. Requires 4-6 hours to lower Potassium
   2. Not a first-line emergent Hyperkalemia Management tool
      1. Marginal efficacy
      2. Potential for lethal colonic necrosis
      3. Delayed onset of action
   3. Use other methods to stabilize hyerkalemia in the Emergency Department
      1. Hyperkalemia stabilization with Calcium
      2. Consider dextrose and Insulin, Nebulized Albuterol and bicarbonate
      3. Dialysis if refractory to other measures
   4. Drug Interaction with oral medications (decreases absorption of other medications)
      1. Avoid other oral medications for at least 3 hours before and 3 hours after Kayexalate
   5. References
      1. Swaminathan and Herbert in Majoewsky (2013) EM:Rap 13(7): 8
6. Efficacy: Kayexalate
   1. Resin with Sorbitol lowered Serum Potassium by 0.5 meq per day
      1. Flinn (1961) N Engl J Med 264: 111-5 [PubMed]
   2. No effect on Potassium level in End-stage renal disease
      1. Gruy-Kapral (1998) J Am Soc Nephrol 9(10):1924-30 [PubMed]
7. Adverse Effects: Kayexalate
   1. Poorly tolerated
   2. Fluid Overload
   3. Acute colonic necrosis
      1. Rare but typically fatal
      2. More common with older preparations containing 70% Sorbitol (instead of current 33% Sorbitol)
      3. However still occurs with non-Sorbitol preparations
      4. Lillemoe (1987) Surgery 101(3): 267-72 [PubMed]
      5. McGovan (2009) South Med J 102(5): 493-7 [PubMed]
      6. Harel (2013) Am J Med 126(3): e9-24 [PubMed]
8. Contraindications: Kayexalate
   1. Congestive Heart Failure
   2. Severe Hypertension
9. Dosing: Kayexalate
   1. Oral
      1. Kayexalate 15 g orally in 50-100 ml of 20% Sorbitol
      2. Although dosing up to 30-60 g has been used, these doses are not recommended
      3. May be repeated every 3-4 hours up to 4 doses/day
   2. Retention Enema
      1. Kayexalate 30-60 grams
      2. Dissolve in 200 ml of 20% Sorbitol or 20% D5W
      3. Retained for 30-60 min (use inflated rectal catheter)
      4. May repeat every 6 hours up to 4 doses per day
10. References
    1. Hochman and Patel in Herbert (2013) EM:Rap 13(12): 8-9