Brands, Medical Use, Clinical Data
- Antihypocalcemic Agents
- Antihypoparathyroid Agents
- Vitamins (Vitamin D)
Brands / Synonyms
Antitanil; Calcamine; DHT; Dht Intensol; Dichystrolum; Dihydral; Dihydrotachysterol; Dygratyl; Hytakerol; Parterol; Tachystin
Used for the treatment of acute, chronic, and latent forms of postoperative tetany, idiopathic tetany, and hypoparathyroidism
Dihydrotachysterol is hydroxylated in the liver to 25-hydroxydihydrotachysterol, which is the major circulating active form of the drug. It does not undergo further hydroxylation by the kidney and therefore is the analogue of 1, 25-dihydroxyvitamin D. Dihydrotachysterol is effective in the elevation of serum calcium by stimulating intestinal calcium absorption and mobilizing bone calcium in the absence of parathyroid hormone and of functioning renal tissue. Dihydrotachysterol also increases renal phosphate excretion.
Mechanism of Action
Once hydroxylated to 25-hydroxydihydrotachysterol, the modified drug binds to the vitamin D receptor. The bound form of the vitamin D receptor serves a transcriptional regulator of bone matrix proteins, inducing the expression of osteocalcin and suppressing synthesis of type I collagen. Vitamin D (when bound to the vitamin D receptor) also stimulates the expression of a number of proteins involved in transporting calcium from the lumen of the intestine, across the epithelial cells and into blood. This stimulates intestinal calcium absorption and increases renal phosphate excretion. These are functions that are normally carried out by the parathyroid hormone.
Biotrnasformation / Drug Metabolism