calcium carbonate + sodium polystyrene sulfonate

This is a combination of two agents, calcium carbonate and sodium polystyrene sulfonate. Calcium carbonate is an inorganic salt commonly used as a calcium supplement and antacid. Sodium polystyrene sulfonate is a cation-exchange resin used to treat hyperkalemia (elevated blood potassium). Sodium polystyrene sulfonate works by exchanging sodium ions for potassium ions in the intestine, thereby binding excess potassium and facilitating its excretion in feces[2][3][6]. The combination may be considered in patients with chronic kidney disease or other conditions requiring both phosphate binding (from calcium carbonate) and potassium lowering (from sodium polystyrene sulfonate), but this combination carries significant risk of drug interaction, including metabolic alkalosis[1][4]. Both drugs are not absorbed systemically; their effects are local to the gastrointestinal tract.