Basic Chemical Information of Paricalcitol

Chemical Name: Paricalcitol

Other Names: 19-nor-1,25-dihydroxyvitamin D2

CAS Number: 131918-61-1

Molecular Formula: C27H44O3

Molecular Weight: 416.64 g/mol

Pharmacological Action

Paricalcitol is a synthetic analog of vitamin D that is used primarily for the treatment and prevention of secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease, especially those undergoing dialysis.

Mechanism of Action:

1.     Vitamin D Receptor Activation:

o    Paricalcitol works by binding to the vitamin D receptor (VDR) in the body's tissues, which then enters the nucleus and modulates gene expression.

o    It selectively activates the VDR, which decreases parathyroid hormone (PTH) synthesis and secretion.

2.     Parathyroid Hormone Reduction:

o    By reducing the levels of parathyroid hormone, paricalcitol helps in alleviating the effects of secondary hyperparathyroidism, such as bone resorption and disturbances in calcium and phosphorus metabolism.

3.     Calcium and Phosphorus Balance:

o    Paricalcitol helps maintain calcium and phosphorus homeostasis by increasing intestinal absorption of calcium and modulating osteoclast and osteoblast activity.

4.     Fibroblast Growth Factor 23 (FGF23) Reduction:

o    It may reduce levels of fibroblast growth factor 23, which plays a role in phosphate excretion and vitamin D metabolism.