Calcitriol



Calcitriol
Systematic (IUPAC) name
(1R,3S)- 5-[2-[(1R,3aR,7aS)-1- [(2R)-6-hydroxy-6-methyl-heptan-2-yl]-
7a-methyl-2,3,3a,5,6,7-hexahydro-1H- inden-4-ylidene]ethylidene]-
4-methylidene-cyclohexane-1,3-diol
Identifiers
CAS number 32222-06-3
ATC code D05AX03
PubChem 134070
DrugBank APRD00246
Chemical data
O3 
Mol. mass 416.64 g/mol
Pharmacokinetic data
Bioavailability  ?
Metabolism Renal
Half life 5–8 hours
Excretion Renal
Therapeutic considerations
Pregnancy cat.

B3 (Au), C (U.S.)

Legal status

S4 (Au), POM (UK)

Routes Oral, IV, topical

Calcitriol (PTH.

Calcitriol is marketed under various trade names including Rocaltrol (Abbott) and Decostriol (Mibe, Jesalis).

Production and function

It is produced in the kidneys via 25-Hydroxyvitamin D3 1-alpha-Hydroxylase by conversion from 25-hydroxycholecalciferol (calcidiol).

This is stimulated by a decrease in serum parathyroid hormone (PTH) levels. It increases blood calcium levels by increasing the absorption of calcium and phosphate from the gastrointestinal tract, increasing calcium and phosphate reabsorption in the kidneys and inhibiting the release of PTH.

Calcitriol is also commonly used as a medication in the treatment of hypocalcemia and osteoporosis.

Metabolism

Calcitriol becomes calcitroic acid through the action of 24-hydroxylase. Calcitroic acid is excreted in the urine.

Indications

Calcitriol is indicated for:[1]

  • Treatment of rickets (infants, children), renal osteodystrophy, chronic renal dialysis
  • Treatment of osteoporosis
  • Prevention of corticosteroid-induced osteoporosis

Calcitriol is also sometimes used topically in the treatment of psoriasis, however the evidence to support its efficacy is inconclusive.[2] The vitamin D analogue calcipotriol is more commonly used for psoriasis.

Adverse effects

The main hypercalcaemia – early symptoms include: nausea, vomiting, constipation, anorexia, apathy, headache, thirst, sweating, and/or polyuria). Compared to other vitamin D compounds in clinical use (cholecalciferol, ergocalciferol), calcitriol has a higher risk of inducing hypercalcaemia. However, such episodes may be shorter and easier to treat due to its relatively short half-life.[1]

See also

Additional images

References

  1. ^ a b Rossi S, editor. Australian Medicines Handbook 2006. Adelaide: Australian Medicines Handbook; 2006. ISBN 0-9757919-2-3
  2. ^ Calcitriol. In: Klasco RK, editor. Drugdex system. vol 128. Greenwood Village (CO): Thomson Micromedex; 2006.
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