Calcitriol 2200872 212112096 2008-05-13T14:15:17Z 141.219.48.137 corrected error: Calcitiol is not Vit D3. {{drugbox | | image = calcitriol.png | width = 280 | IUPAC_name = (1''R'',3''S'')- 5-<nowiki>[2-[(</nowiki>1R,3a''R'',7a''S'')-1- <nowiki>[</nowiki>(2''R'')-6-hydroxy-6-methyl-heptan-2-yl<nowiki>]</nowiki>- <br />7a-methyl-2,3,3a,5,6,7-hexahydro-1''H''- inden-4-ylidene]ethylidene]-<br /> 4-methylidene-cyclohexane-1,3-diol | CAS_number = 32222-06-3 | ATC_prefix= A11 | ATC_suffix= CC04 | ATC_supplemental = {{ATC|D05|AX03}} | PubChem = 134070 | DrugBank = APRD00246 | C=27 | H=44 | O=3 | molecular_weight = 416.64 g/mol | bioavailability = | metabolism = [[Renal]] | elimination_half-life = 5–8 hours | excretion = Renal | pregnancy_category = B3 <small>([[Australia|Au]])</small>, C <small>([[United States|U.S.]])</small> | legal_status = S4 <small>(Au)</small>, POM <small>([[United Kingdom|UK]])</small> | routes_of_administration = Oral, [[intravenous|IV]], topical }} '''Calcitriol''' ([[International Nonproprietary Name|INN]]) ({{pronEng|ˌkælsɨˈtraɪɒl/, /ˌkælˈsɨtriːɒl}}) or '''1,25-dihydroxycholecalciferol''' (abbreviated '''1,25-(OH)<sub>2</sub>D<sub>3</sub>''') (also known as calitrol) is the active form of [[vitamin D]] found in the body (1,25(OH)2D3). It increases the absorption of [[calcium]] and [[phosphate]] from the [[gastrointestinal tract]] and [[kidneys]] and inhibits release of [[calcitonin]]. Calcitriol is marketed under various trade names including '''Rocaltrol''' ([[Hoffman-La Roche|Roche]]), '''Calcijex''' ([[Abbott Laboratories|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 [[calcium]] and/or [[phosphate]] (PO<sub>4</sub><sup>3−</sup>), and an increase in [[parathyroid hormone]] (PTH) and/or [[prolactin]] 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 [[calcitonin]]. Calcitriol acts in concert with [[parathyroid hormone]] (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:<ref name="AMH2006">Rossi S, editor. [[Australian Medicines Handbook]] 2006. Adelaide: Australian Medicines Handbook; 2006. ISBN 0-9757919-2-3</ref> *Treatment of [[hypocalcaemia]] – [[hypoparathyroidism]], [[osteomalacia]] (adults), [[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.<ref name="MicromedexDrugdex">Calcitriol. In: Klasco RK, editor. Drugdex system. vol 128. Greenwood Village (CO): Thomson Micromedex; 2006.</ref> The vitamin D analogue [[calcipotriol]] is more commonly used for psoriasis. ==Adverse effects== The main [[adverse drug reaction]] associated with calcitriol therapy is [[hypercalcaemia]] – early symptoms include: nausea, vomiting, constipation, [[anorexia (symptom)|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 [[elimination half-life|half-life]].<ref name="AMH2006" /> ==See also== * [[Vitamin D#Synthesis mechanism .28form 3.29]] ==Additional images== <gallery> Image:Calcitriol-Synthesis.png|Calcitriol synthesis </gallery> ==References== {{reflist}} {{Hormones}} {{Vitamin}} {{Antipsoriatics}} [[Category:Vitamins]] [[Category:Secosteroids]] [[de:Calcitriol]] [[dv:ކެލްސިޓްރިއޯލް]] [[es:Calcitriol]] [[mk:Калцитриол]] [[pl:Kalcytriol]] [[pt:Calcitriol]]