Calcitriol (INN) (IPA: ) or 1,25-dihydroxycholecalciferol (abbreviated 1,25-(OH)₂D₃) is the active form of vitamin D found in the body (vitamin D₃). It is produced in the kidneys by conversion from 25-hydroxycholecalciferol (calcidiol) and regulates calcium levels by increasing the absorption of calcium from the gastrointestinal tract. Calcitriol is also commonly used as a medication in the treament of hypocalcaemia and osteoporosis. Calcitriol is marketed under various trade names including Rocaltrol (Roche) and Calcijex (Abbott).

Indications

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Calcitriol is indicated for:Rossi S, editor. Australian Medicines Handbook 2006. Adelaide: Australian Medicines Handbook; 2006. ISBN 0-9757919-2-3

• Treatment of hypocalcaemia – hypoparathyroidism, osteomalacia (rickets), renal osteodystrophy, chronic renal dialysis
• Treatment of osteoporosis
• Prevention of corticosteroid-induced osteoporosis

Calcitriol is also sometimes used topically in the treament of psoriasis, however the evidence to support its efficacy is inconclusive.Calcitriol. In: Klasco RK, editor. Drugdex system. vol 128. Greenwood Village (CO): Thomson Micromedex; 2006. The vitamin D analogue calcipotriol is more commonly used for psoriasis.

Adverse effects

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The main adverse drug reaction associated with calcitriol therapy is 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.

References

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Vitamins