ATC Group: V03AE Drugs for treatment of hyperkalemia and hyperphosphatemia

Calcium is an endogenous ion of the body essential for the maintenance of a number of physiologic processes. It participates as an integral factor in the maintenance of the functional integrity of the nervous system, in the contractile mechanisms of muscle tissue, in the clotting of blood, and in the formation of the major structural material of the skeleton. Soluble calcium salts are commonly used in the treatment of calcium deficiency.

Colestilan is a non-absorbed, non-calcium, non-metallic phosphate-binding polymer. The binding sites become partially protonated in the stomach and interact through ionic and hydrogen bonding with both dietary phosphate anions and bile acids in the duodenum. By binding phosphate from food in the digestive tract, colestilan lowers the serum phosphorus concentration. Colestilan also binds bile acids, thereby lowering the serum LDL-cholesterol concentration.

Ferric citrate is a phosphate binder and iron replacement product. It is used for the control of serum phosphorus levels and the treatment of iron deficiency anemia in adult patients with chronic kidney disease on dialysis.

Iron sucrose is composed of a polynuclear iron(III)-hydroxide core surrounded by a large number of non-covalently bound sucrose molecules. The polynuclear iron core has a structure similar to that of the core of the physiological iron storage protein ferritin. The complex is designed to provide, in a controlled manner, utilisable iron for the iron transport and storage proteins in the body (i.e., transferrin and ferritin, respectively).

Lanthanum is indicated as a phosphate binding agent for use in the control of hyperphosphataemia.

Patiromer is a non-absorbed, cation exchange polymer that contains a calcium-sorbitol complex as a counterion. Patiromer increases faecal potassium excretion through binding of potassium in the lumen of the gastrointestinal tract. Binding of potassium reduces the concentration of free potassium in the gastrointestinal lumen, resulting in a reduction of serum potassium levels.

Sevelamer is a non-absorbed phosphate binding crosslinked polymer, free of metal and calcium. Sevelamer contains multiple amines separated by one carbon from the polymer backbone which become protonated in the stomach. These protonated amines bind negatively charged ions such as dietary phosphate in the intestine.

Sodium zirconium cyclosilicate is a non-absorbed, non-polymer inorganic powder with a uniform micropore structure that preferentially captures potassium in exchange for hydrogen and sodium cations. Sodium zirconium cyclosilicate captures potassium throughout the entire gastrointestinal (GI) tract and reduces the concentration of free potassium in the GI lumen, thereby lowering serum potassium levels and increasing faecal potassium excretion to resolve hyperkalaemia.

Sucroferric oxyhydroxide is also known as a mixture of polynuclear iron(III)-oxyhydroxide (pn-FeOOH), sucrose and starches. Phosphate binding takes place by ligand exchange between hydroxyl groups and/or water and the phosphate ions throughout the physiological pH range of the gastrointestinal tract. Serum phosphorus levels are reduced as a consequence of the reduced dietary phosphate absorption.