Calcium polystyrene sulfonate is indicated for the treatment of hyperkalemia (elevated serum potassium levels), particularly in patients with chronic kidney disease or acute renal impairment. It works as a cation-exchange resin, binding potassium in the gastrointestinal tract and promoting its elimination in exchange for calcium. Its key advantage is effective reduction of potassium levels without adding sodium load, making it especially suitable for patients where sodium restriction is important, such as those with heart failure or hypertension. In hospital settings, it is used as part of a comprehensive approach to hyperkalemia management, helping prevent life-threatening complications such as cardiac arrhythmias. It can be administered orally or rectally, providing flexibility depending on patient condition. Its targeted mechanism and clinical reliability make it a valuable option in nephrology and emergency care.