Chemical Information

• Common Name: Alfacalcidol

• CAS Number: 41294-56-8

• Molecular Formula: C27H44O2

• Molecular Weight: 400.64 g/mol

• IUPAC Name:      (5Z,7E)-(1R,3aR,7aR)-1-[(2R)-6-hydroxy-6-methylheptan-2-yl]-7a-methyl-2-[(1E,3E,5R)-5,6-dimethylhepta-1,3-dien-1-yl]octahydro-1H-inden-5-ol

• Synonyms: 1α-Hydroxycholecalciferol, 1α-OH-D3

Pharmacological Action

Alfacalcidol is a vitamin D analog used primarily in managing diseases related to calcium and phosphate metabolism, such as osteoporosis and rickets. Here are its primary pharmacological actions:

1.     Regulation of Calcium and Phosphate Metabolism:

o    Bone Mineralization: Alfacalcidol aids in the regulation of calcium and phosphorus levels by promoting the intestinal absorption of these minerals, which is essential for maintaining proper bone structure and function.

o    Renal Excretion: It decreases the renal excretion of calcium and phosphate, helping in maintaining their levels in the bloodstream.

2.     Conversion to Active Form:

o    Hepatic Activation: Alfacalcidol is converted in the liver to calcitriol (1,25-dihydroxyvitamin D3), the active form of vitamin D. Calcitriol exerts various biological effects similar to naturally occurring vitamin D.

3.     Immunomodulation:

o    The active form of Alfacalcidol has been shown to have effects on the immune system, which may be beneficial in certain autoimmune diseases.

4.     Parathyroid Hormone (PTH) Suppression:

o    Hyperparathyroidism: Alfacalcidol can suppress PTH secretion, which can be particularly beneficial in managing secondary hyperparathyroidism associated with chronic kidney disease.