Sodium Powder is a cation exchange resin that is administered orally to lower excessive potassium levels in the blood. In the intestine, sodium polystyrene sulfonate eliminates potassium by changing sodium ions for potassium ions. The bulk of cation exchange appears to occur in the large intestine, where potassium ions are expelled in larger quantities. According to in-vitro research, each gramme of resin eliminates around 3 mEq of potassium. In patients, however, real potassium elimination is closer to 1 mEq per gramme of medicine. Because sodium polystyrene sulfonate takes several hours to start functioning, it should not be used to treat life-threatening episodes of acute hyperkalemia.