Kayexalate (sodium polystyrene sulfonate) powder is used to treat high potassium in the blood. It is a cation-binding exchange resin that inhibits the absorption of potassium from the gastrointestinal tract (along with other cations)

Sodium polystyrene sulfonate (Kayexalate) Uses:

• Hyperkalemia:

  • It is used in the maintenance treatment of hyperkalemia.
  • Limitations of use:
    • Sodium polystyrene sulfonate should not be used as an emergency treatment for life-threatening hyperkalemia due to delayed onset of action.

Other novel drugs used to treat hyperkalemia include sodium zirconium cyclosilicate (Lokelma) and Patiromer (Veltassa). Some of the important differences between Sodium polystyrene sulfonate (Kayexalate) powder and Lokelma (Sodium zirconium cyclosilicate) are highlighted in the article: Lokelma vs Kayexalate for the treatment of Hyperkalemia.

Sodium polystyrene sulfonate (Kayexalate) Dose in Adults

Sodium polystyrene sulfonate (Kayexalate) Dose in the treatment of Hyperkalemia:

• P/O:
  • 15 g 1-4 times daily.
• Rectal:
  • 30-50 g every 6 hours

Sodium polystyrene sulfonate (Kayexalate) Dose in Children

Sodium polystyrene sulfonate (Kayexalate) Dose in the treatment of Hyperkalemia:

Note:

• Used when necessary to increase potassium excretion, typically not first-line.
• Sodium polystyrene sulfonate should not be used as an emergency treatment for life-threatening hyperkalemia due to delayed onset of action.

• Weight-based dosing:

  • Infants, Children, and Adolescents:

    • P/O or via nasogastric:

      • Every 6 hours, 1 g/kg/dose.
      • Max dose: 15 g/dose.
    • Note:
      • The oral route is more effective than the rectal & is preferred.

    • Rectal:

      • Every 2-6 hours, 1 g/kg/dose.
      • Max dose range: 30 to 50 g/dose.
      • Retain at least 15-60 mins.
    • Note:
      • Sorbitolfree preparations are preferred.

• Exchange-ratio-based dosing:

  • Infants and small children:

    • Oral, nasogastric, rectal:

      • 1 mEq K /g of sodium polystyrene sulfonate resin as the basis for calculation.

Sodium polystyrene sulfonate (Kayexalate) for the pretreatment of formula or expressed breast milk to decrease potassium load for renal failure patients:

• Infants and Children:

  • Infant and Enteral formula:

    • Adjust dose based on patient serum potassium trends, 5-2.6 g/100 mL of formula, or 0.25 to 1g/mEq K content of the formula.
    • Shake vigorously to mix, allow to sit under refrigeration for 30-60 mins after addition of the resin, then decant liquid for feed and leave precipitate at the bottom.
    • The extent of potassium removal depends on the formula.
    • In 1 trial, Similac PM 60/40 samples showed significant decreases at additive amounts of 0.25 to 1 g/mEq K content of formula versus Suplena which only showed a significant reduction of K concentrations in the formula at 1 g/mEq K content of the formula.
    • Other electrolyte concentrations may also be decreased (eg, Ca, Mg, Cu, Zn) and significant increases in sodium concentrations of the formula were consistently reported.
    • Patients should be examined and monitored closely.

  • Expressed breast milk:

    • Usual dose:

      • ~1 g/100 mL.
      • Adjust based on patient serum potassium trends.

    • Reported dose range:

      • 0.4-1.5 g/100 mL of expressed breast milk.
      • After the addition of the resin, shake vigorously to mix, allow to sit under refrigeration for 60 mins, then decant liquid for infant feed and leave precipitate at the bottom.
      • In addition to decreasing the potassium load of the feed (subsequently patient's serum K), other electrolyte concentrations may also be decreased (eg, Ca, Mg, Cu, Zn) & sodium concentrations (breast milk and serum) increased.
      • Patients should be monitored closely.

Pregnancy Risk Factor C

• Studies on animal reproduction have not been done.
• Sodium polystyrene sulfonate cannot be absorbed systemically after it has been administered orally or rectally.
• It is not possible to use during pregnancy to expose the fetus to significant amounts.

Sodium polystyrene sulfonate use during breastfeeding:

• Systemic absorption of sodium polystyrene sulfurate is not possible.
• It is not likely that breastfeeding will result in significant exposure for a child who is breastfed.

Sodium polystyrene sulfonate (Kayexalate) Dose in Kidney Disease:

• In the manufacturer's labeling, there are no dosage adjustments provided.
• Use cautiously.
• In patients with renal insufficiency or failure, risks of gastrointestinal adverse effects are greater.

Sodium polystyrene sulfonate (Kayexalate) Dose in Liver disease:

• In the manufacturer's labeling, there are no dosage adjustments provided.

Side effects of Sodium polystyrene sulfonate (Kayexalate):

• Endocrine & Metabolic:

  • Hypernatremia
  • Hypocalcemia
  • Hypokalemia
  • Hypomagnesemia
  • Sodium Retention

• Gastrointestinal:

  • Anorexia
  • Constipation
  • Diarrhea
  • Fecal Impaction
  • Nausea
  • Vomiting

Contraindications to Sodium polystyrene sulfonate (Kayexalate):

• Hypersensitivity to sodium polystyrene sulfurate resins and polystyrene-sulfonate sulfonate emulsifiers or any other component of the formulation
• Hypokalemia (exclusion Kayexalate).
• Obstructive bowel disease.
• Low gut motility in neonates
• Oral administration for neonates
• Rectal administration for neonates (sorbitol-containing formulations only).

Warnings and precautions

• Aspiration:

  • Inhalation of sodium polystyrene-sulfonate particles has been linked to acute bronchitis and bronchopneumonia.
  • Patients who have impaired gag reflex or altered consciousness levels, or are prone to regurgitation, may be at greater risk.
  • Assist the patient with their care in a standing position.

• Electrolyte disturbances:

  • Hypokalemia severe may be possible.
  • It is recommended to monitor serum potassium every 24 hours.
  • ECG monitoring might be suitable for some patients.
  • Other cation concentrations could be affected by Cation-exchange resins, causing a decrease in serum magnesium and calcium.

• Impaction of the fecal feces:

  • Fecal impaction can occur in elderly patients especially if the oral dose is large.
  • Rectal administration has been linked to fecal impurity in children.

• Intestinal necrosis:

  • Intestinal necrosis, including fatalities, has been reported, especially when sorbitol is used.
  • It is not recommended to take sorbitol with sorbitol.
  • Increased risk could be due to a history of surgery or intestinal disease, hypovolemia, prematurity or renal insufficiency.
  • Only use in patients with normal bowel function.
  • Avoid the use of this product in patients who are at risk for constipation and impaction until normal bowel function returns.
  • If constipation occurs, discontinue using the product.

• Cardiovascular disease

  • Patients with severe hypertension and/or heart failure should be cautious.
  • The condition may be exacerbated by sodium overload.

• Edema

  • Patients with edema should be cautious.
  • The condition may be aggravated by sodium overload.

• Renal impairment

  • Patients with impaired renal function should be cautious.

Sodium polystyrene sulfonate: Drug Interaction

Note: Drug Interaction Categories:

• Risk Factor C: Monitor When Using Combination
• Risk Factor D: Consider Treatment Modification
• Risk Factor X: Avoid Concomitant Use

Monitoring parameters:

• Serum electrolytes (potassium, sodium, calcium, magnesium).
• ECG in selected patients.
• Signs/symptoms of fluid overload in patients sensitive to sodium intake (eg, heart failure, hypertension, edema).

How to administer Sodium polystyrene sulfonate (Kayexalate)?

• Oral or NG:

  • Administer orally or via NG tube at least 3 hours before or 3 hours after other medications with the patient in an upright position (patients with gastroparesis may require a 6-hour separation).
  • Do not mix in orange juice or in any fruit juice known to contain potassium.
  • Prior to administration, shake the suspension well.
  • Chilling the oral mixture will increase palatability.
  • Sodium polystyrene sulfonate suspension may also be added to the patient's food (with the exception of potassium-containing food such as bananas and orange juice).

• Rectal:

  • Administer cleansing enema first.
  • Administer sodium polystyrene sulfonate as a warm emulsion (body temperature).
  • The solution should be agitated gently during administration.
  • If possible, retain the enema in the colon for at least 30 to 60 minutes and for several hours.
  • Irrigate the colon with a nonsodium-containing solution to remove resin, once retention time is complete.

Mechanism of action of Sodium polystyrene sulfonate (Kayexalate):

• Before the resin is removed from the body, it is possible to remove potassium by exchanging sodium for potassium ions in your intestine (especially large intestine).
• In vivo the practical exchange capacity is 1 mg potassium per 1g resin. The in vitro capacity, however, is 3.1 mg of potassium per 1g resin. Therefore, it is important to monitor serum electrolytes closely.

The onset of action:

• Hours to days

Absorption:

• None

Excretion:

• Completely feces (primarily as potassium polystyrene sulfonate)

International Brands of Sodium polystyrene sulfonate:

• Kalexate
• Kayexalate
• Kionex
• SPS
• Kexelate
• Kuzem
• Resinokaten
• Resinsodio
• Resonium
• Resonium A

Sodium polystyrene sulfonate Brand Names in Pakistan:

Kayexalate Powder (100 gms, 450 gms)