Products
Alfacalcidol is commercially available in Germany in the form of soft capsules, drops, and as a solution for injection (e.g., EinsAlpha). It is not registered in many countries.
Structure and properties
Alfacalcidol (C27H44O2, Mr = 400.6 g/mol) corresponds to 1-hydroxycholecalciferol. It is in the form of white crystals and is practically insoluble in water. The substance is sensitive to air, heat and light.
Effects
Alfacalcidol (ATC A11CC03) is a direct precursor of calcitriol, to which it is rapidly converted in the liver. Unlike cholecalciferol, it is already hydroxylated and 1α-hydroxylation at the kidney is therefore not necessary. It leads to an increase in decreased intestinal calcium absorption in impaired renal function.
Indications
Vitamin D deficiency, diseases in which 1α-hydroxylation in the kidney is impaired in vitamin D metabolism.