Calcifediol

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[edit] BRAND NAMES

[edit] STRUCTURE

Calcifediol.png

[edit] MECHANISM OF ACTION

Calcifediol (INN), also known as calcidiol, 25-hydroxycholecalciferol, or 25-hydroxyvitamin D (abbreviated 25(OH)D) is a prehormone that is produced in the liver by hydroxylation of vitamin D3 (cholecalciferol).

Calcifediol is the circulating form of vitamin D. The administration of calcifediol bypasses the hepatic phase of vitamin D metabolism and thereby directly supplies the body with this first metabolite. Calcifediol undergoes then a second hydroxylation in the kidneys to the physiologically active metabolite (active form of vitamin D), calcitriol also called 1,25-dihydroxy vitamin D3 or 1,25-(OH)2D3).

The essential role of vitamin D is in the intestine, where it increases the capacity to absorb calcium and phosphorus, and in the skeleton, where it promotes bone mineralization.

Calcifediol has a half-life of approximately 18 to 21 days and is stored in fat to a lesser extent than vitamin D, probably because it is less lipid-soluble.

[edit] INDICATIONS

Infants and children:

  • Rickets due to deficiency.
  • Prevention of calcium disorders secondary to corticosteroid or anticonvulsant therapy.
  • Prevention of vitamin D deficiency in renal failure.

Adults:

  • Osteomalacia (nutritional or due to malabsorption).
  • Treatment of vitamin D deficiency.
  • Prevention of calcium disorders secondary to corticosteroid or anticonvulsant therapy.
  • Prevention of vitamin D deficiency in renal failure.

[edit] DOSAGE

Oral solution, drops, 15 mg/100 ml (one drop = 5 μg, 1 ml = 30 drops):

Dilute the drops in a small amount of water, milk or fruit juice.

Infants and children:

  • Rickets due to deficiency: 2 to 4 drops daily.
  • Prevention of calcium disorders:
    • secondary to corticosteroid therapy: 1 to 4 drops daily;
    • secondary to anticonvulsants: 1 to 5 drops daily.
  • Prevention of native vitamin D deficiency in renal failure: 2 to 6 drops daily.


Adults:

  • Osteomalacia:
    • nutritional: 2 to 5 drops daily;
    • due to malabsorption, or anticonvulsant therapy: 4 to 10 drops daily.
  • Treatment of vitamin D deficiency: 2 to 5 drops daily.
  • Prevention of calcium disorders:
    • secondary to corticosteroid therapy: 1 to 4 drops daily;
    • secondary to anticonvulsants: 1 to 5 drops daily.
  • Prevention of native vitamin D deficiency in renal failure: 2 to 6 drops daily.


[edit] CONTRAINDICATIONS

  • Hypersensitivity to any of the ingredients.
  • Hypercalcemia, hypercalciuria, calcium lithiasis.

[edit] WARNINGS AND PRECAUTIONS

In case of renal insufficiency, it is necessary to monitor creatinine clearance and phosphoremia and to avoid hypercalcemia, even moderate.

To avoid overdosage, take into account the total intake of vitamin D when concomitantly using other treatments containing vitamin D or its derivatives.

In case of high calcium intake, frequent control of urinary calcium is essential.

Laboratory tests: the administration of Calcifediol requires a determination of serum and urinary calcium levels before initiating treatment and repeated monitoring, in order to avoid a risk of overdosage, for 1 to 3 months after initiating treatment, then generally about every 3 months (in case of prolonged treatment):

  • if serum calcium exceeds 105 mg/l (2.62 mmol/l), the treatment must be discontinued for at least 3 weeks;
  • if urinary calcium exceeds 4 mg/kg/day (0.1 mmol/kg/day), abundant fluid intake should be recommended (for adults, 2 liters of low mineral content water per day) and the treatment should be discontinued at least temporarily. In

children, normal urinary calcium levels are less than 5 mg/kg/day (0.125 mmol/kg/day).

[edit] INTERACTIONS

Thiazide diuretics (i.e. Hydrochlorothiazide): due to the risk of hypercalcemia, use the lowest recommended dose and perform more frequent monitoring of serum calcium.

[edit] PREGNANCY AND LACTATION

  • Pregnancy: The administration of Calcifediol may be envisioned during pregnancy, but there are no dose-defining studies in pregnant women. Nonetheless, the daily dosage should not exceed 15 μg (2 to 3 drops/day).
  • Lactation: When necessary, vitamin D may be prescribed to breastfeeding women. However, since it is excreted in breast milk and in order to avoid overdosage, take into account any vitamin D administered to the infant.

[edit] SIDE EFFECTS

Undesirable effects do not occur at therapeutic doses, but in case of overdosage.

Symptoms of overdosage:

  • clinical: anorexia, nausea, vomiting; polyuria-polydipsia, dehydration; hypertension; cessation of growth; calcium lithiasis, tissue calcifications, particularly renal and vascular;
  • biological: hypercalciuria, hypercalcemia, hyperphosphoremia, hyperphosphaturia, renal insufficiency.

Emergency action: intensive care in a specialized facility in case of severe hypercalcemia.

[edit] RELATED LINKS

Calcium and phosphate homeostasis, including discussion of vitamin D metabolism and the actions of PTH
How osteoporosis develops

[edit] BIBLIOGRAPHY

[edit] REFERENCES