Description

Simple

A medication similar to vitamin D that is used to treat hyperparathyroidism, a hormonal disorder, as well as to give nutrition to patients on dialysis.

Clinical

An active metabolite of vitamin D that is used to treat hyperparathyroidism and is also used in dialysis patients to combat hypocalcemia.

Overview

Calcitriol is an active metabolite of vitamin D with 3 hydroxyl (OH) groups and is commonly referred to as 1,25-dihydroxycholecalciferol, or 1alpha,25-dihydroxyvitamin D3, 1,25-dihydroxyvitamin D3. It is produced in the body after series of conversion steps of 7-dehydrocholesterol from exposure to UV light. 7-dehydrocholesterol is converted to [DB00169] (vitamin D3) in the skin, which is then converted to [DB00146] in the liver and kidneys. [DB00146] undergoes hydroxylation to form calcitriol via 1α-hydroxylase (CYP27B1) activity [4]. Calcitriol is considered to be the most potent metabolite of vitamin D in humans [1]. Renal production of calcitriol is stimulated in response to PTH, low calcium and low phosphate [4]. Calcitriol plays a role in plasma calcium regulation in concert with parathyroid hormone (PTH) by enhancing absorption of dietary calcium and phosphate from the gastrointesti... Read more

Pharmacology

Indication

Used to treat vitamin D deficiency or insufficiency, refractory rickets (vitamin D resistant rickets), familial hypophosphatemia and hypoparathyroidism, and in the management of hypocalcemia and renal osteodystrophy in patients with chronic renal failure undergoing dialysis. Also used in conjunction... Read more

Pharmacodynamic

Calcitriol is a biologically active calcitrophic hormone with anti-osteoporotic, immunomodulatory, anticarcinogenic, antipsoriatic, antioxidant, and mood-modulatory activities. Its main sites of action are the intestine, bone, kidney and parathyroid hormone [FDA Label]. Calcitriol is a ligand for th... Read more

Mechanism of action

The mechanism of action of calcitriol in the treatment of psoriasis is accounted for by their antiproliferative activity for keratinocytes and their stimulation of epidermal cell differentiation. The anticarcinogenic activity of the active form of Calcitriol appears to be correlated with cellular vi... Read more

Absorption

Upon administration, calcitriol is rapidly absorbed from the intestines. When a single oral dose of 0.5 mcg of calcitriol was administered, the mean serum concentrations of calcitriol rose from a baseline value of 40.0±4.4 (SD) pg/mL to 60.0±4.4 pg/mL at 2 hours, and declined to 53.0±6.9 at 4 hours,... Read more

Protein binding

Calcitriol is approximately 99.9% bound in blood, mostly by an alpha-globulin vitamin D binding protein [FDA Label].

Volume of distribution

Upon intravenous administration, the volume of distribution of calcitriol was 0.49±0.14 L/kg in healthy male volunteers and 0.27±0.06 l/kg in uraemic male patients participating in a pharmacokinetic study [ Read more

Clearance

The metabolic clearance rate was 23.5±4.34 ml/min in healthy male volunteers and 10.1±1.35 ml/min in male patients with uraemia [ Read more

Half life

After administration of single oral doses, the elimination half life was 5-8 hours [FDA Label].

Route of elimination

In normal subjects, approximately 27% and 7% of the radioactivity appeared in the feces and urine, respectively, within 24 hours [FDA Label]. Calcitriol undergoes enterohepatic recycling and biliary excretion. The metabolites of calcitriol are excreted primarily in feces. Cumulative excretion of rad... Read more

Toxicity

LD50 (oral, rat) = 620 μg/kg; LD50 (intraperitoneal, rat) > 5 mg/kg [MSDS].

Symptoms of calcitriol toxicity mirrors the early and late signs and symptoms of vitamin D intoxication associated with hypercalcemia [ Read more

Adverse Effects

Contraindications

  • Regions: US
  • Patient Conditions:
      • Name: Evidence of vitamin D toxicity
      • Drugbank Id: DBCOND0107477
  • Regions: US
  • Patient Conditions:
      • Name: Hypercalcemia
      • Drugbank Id: DBCOND0003950

Food Interactions

    Information currently not available.

Interactions

Type in a drug name to check for interaction with Calcitriol
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  • Paracetamol(acetaminophen)
  • Paxil(paroxetine)
  • Pamelor(nortriptyline)
  • Panadol(acetaminophen)
  • Patanol(olopatadine ophthalmic)
  • Pataday(olopatadine ophthalmic)
  • Parnate(tranylcypromine)
  • Pazeo(olopatadine ophthalmic)
(R)-warfarin
The metabolism of (R)-warfarin can be increased when combined with Calcitriol.
(S)-Warfarin
The metabolism of (S)-Warfarin can be increased when combined with Calcitriol.
1alpha-Hydroxyvitamin D5
The risk or severity of adverse effects can be increased when Calcitriol is combined with 1alpha-Hydroxyvitamin D5.
1alpha,24S-Dihydroxyvitamin D2
The risk or severity of adverse effects can be increased when Calcitriol is combined with 1alpha,24S-Dihydroxyvitamin D2.
4-hydroxycoumarin
The metabolism of 4-hydroxycoumarin can be increased when combined with Calcitriol.
9-aminocamptothecin
The metabolism of 9-aminocamptothecin can be increased when combined with Calcitriol.
Acenocoumarol
The metabolism of Acenocoumarol can be increased when combined with Calcitriol.
Acetyldigitoxin
The risk or severity of ventricular arrhythmias and Cardiac Arrhythmia can be increased when Calcitriol is combined with Acetyldigitoxin.
Acetyldigoxin
The risk or severity of ventricular arrhythmias and Cardiac Arrhythmia can be increased when Calcitriol is combined with Acetyldigoxin.
Albendazole
The metabolism of Albendazole can be increased when combined with Calcitriol.
Aldosterone
The therapeutic efficacy of Calcitriol can be decreased when used in combination with Aldosterone.
Alfacalcidol
The risk or severity of adverse effects can be increased when Calcitriol is combined with Alfacalcidol.
Alfentanil
The metabolism of Alfentanil can be increased when combined with Calcitriol.
Allylestrenol
The metabolism of Allylestrenol can be increased when combined with Calcitriol.
Alpelisib
The metabolism of Alpelisib can be increased when combined with Calcitriol.
Alprazolam
The metabolism of Alprazolam can be increased when combined with Calcitriol.
Aluminum hydroxide
The serum concentration of Aluminum hydroxide can be increased when it is combined with Calcitriol.
Aminophylline
The metabolism of Aminophylline can be increased when combined with Calcitriol.
Amiodarone
The metabolism of Amiodarone can be increased when combined with Calcitriol.
Amlodipine
The metabolism of Amlodipine can be increased when combined with Calcitriol.
10 References
  1. 1 . Brawer MK: Recent Progress in the Treatment of Advanced Prostate Cancer With Intermittent Dose-Intense Calcitriol (DN-101). Rev Urol. 2007 Winter;9(1):1-8.PubMed: 17396166
  2. 2 . Beer TM, Javle M, Lam GN, Henner WD, Wong A, Trump DL: Pharmacokinetics and tolerability of a single dose of DN-101, a new formulation of calcitriol, in patients with cancer. Clin Cancer Res. 2005 Nov 1;11(21):7794-9.PubMed: 16278401
  3. 3 . Zemel MB, Sun X: Calcitriol and energy metabolism. Nutr Rev. 2008 Oct;66(10 Suppl 2):S139-46. doi: 10.1111/j.1753-4887.2008.00099.x.PubMed: 18844841
  4. 4 . Rodriguez M, Munoz-Castaneda JR, Almaden Y: Therapeutic use of calcitriol. Curr Vasc Pharmacol. 2014 Mar;12(2):294-9.PubMed: 23713873
  5. 5 . Dechant KL, Goa KL: Calcitriol. A review of its use in the treatment of postmenopausal osteoporosis and its potential in corticosteroid-induced osteoporosis. Drugs Aging. 1994 Oct;5(4):300-17. doi: 10.2165/00002512-199405040-00006.PubMed: 7827399
  6. 6 . Toussaint ND, Damasiewicz MJ: Do the benefits of using calcitriol and other vitamin D receptor activators in patients with chronic kidney disease outweigh the harms? Nephrology (Carlton). 2017 Mar;22 Suppl 2:51-56. doi: 10.1111/nep.13026.PubMed: 28429545
  7. 7 . Farach-Carson MC, Nemere I: Membrane receptors for vitamin D steroid hormones: potential new drug targets. Curr Drug Targets. 2003 Jan;4(1):67-76.PubMed: 12528991
  8. 8 . Brandi L, Egfjord M, Olgaard K: Pharmacokinetics of 1,25(OH)2D3 and 1α(OH)D3 in normal and uraemic men Nephrology Dialysis Transplantation. 2002 May 1;17(5):829–842.PubMed:
  9. 9 . Takami M, Fujimaki K, Nishimura MI, Iwashima M: Cutting Edge: AhR Is a Molecular Target of Calcitriol in Human T Cells. J Immunol. 2015 Sep 15;195(6):2520-3. doi: 10.4049/jimmunol.1500344. Epub 2015 Aug 14.PubMed: 26276877
  10. 10 . 1,25-DIHYDROXYCHOLECALCIFEROL - National Library of Medicine HSDB Database - ToxNet - NIH Link