Calcium Polystyrene Sulphonate is a potassium-binding cation exchange resin used in the management of hyperkalemia. It works in the gastrointestinal tract by exchanging calcium ions for potassium ions, which are then excreted in the feces. It is particularly useful in patients with chronic kidney disease (CKD) or end-stage renal disease (ESRD) who cannot tolerate sodium-based resins or are on fluid restriction.
Adult: Oral/Rectal: 15g, 1 to 4 times daily. Usual starting dose is 15g once or twice daily. Dose must be individualized based on serum potassium levels. It is typically administered as a suspension in water or a sorbitol-free vehicle.
Note: ORAL: Mix the 15g powder thoroughly in at least 60-120 mL of water or a sugar-free liquid (e.g., plain water). Do NOT heat. Administer immediately after mixing. Can be taken with or without food, but consistency in timing relative to meals is advised. RECTAL (Enema): For patients who cannot take orally. 30-50g is suspended in 100 mL of aqueous vehicle (e.g., methylcellulose, water) and administered as a retention enema, retained for 30-60 minutes if possible, followed by a cleansing enema. The 15g sachet may be used as part of this preparation.
Calcium Polystyrene Sulphonate is a non-absorbable cation-exchange resin. In the large intestine (primarily the colon), where the pH is neutral to slightly alkaline, the resin releases calcium ions in exchange for other cations, predominantly potassium and to a lesser extent ammonium (NH4+). The freed calcium is absorbed or excreted, while the potassium-bound resin is excreted in the stool, thereby reducing the total body potassium load.
Pregnancy: Category C: Animal reproduction studies not conducted. Use only if clearly needed and potential benefit justifies potential risk to the fetus. Electrolyte imbalance can affect both mother and fetus.
Driving: No effect. The drug does not cause sedation or impair cognitive function.
| Oral Potassium-Sparing Diuretics (e.g., Spironolactone, Amiloride) | Antagonistic effect; reduces efficacy of the potassium binder. | Moderate |
| Oral Potassium Supplements (e.g., KCl) | Antagonistic effect; counteracts the potassium-lowering effect. | Major |
| Oral Magnesium Supplements (e.g., Magnesium Oxide) or Antacids containing Magnesium/Aluminum | May be bound by the resin, reducing their absorption and efficacy. Can also lead to systemic alkalosis with aluminum-based antacids. | Moderate |
| Oral Calcium Supplements or Vitamin D Analogues (e.g., Calcitriol) | Increased risk of hypercalcemia. | Moderate |
| Oral Thyroid Hormones (e.g., Levothyroxine) | Resin may bind and reduce absorption. Administer at least 4-6 hours apart. | Moderate |
| Oral Lithium | Resin may bind lithium, reducing its serum levels and efficacy. | Major |
| Oral Digoxin | Hypokalemia or hypomagnesemia induced by the resin can potentiate digoxin toxicity. | Major |
| Oral Iron Supplements | May reduce absorption of iron. | Moderate |
Same composition (Calcium Polystyrene Sulphonate (15gm)), different brands: