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Uses

Hypocalcemia Secondary to Chronic Renal Disease

Management of hypocalcemia and resultant metabolic bone disease in adult patients with chronic renal disease undergoing dialysis.

Enhances calcium absorption, reduces serum alkaline phosphatase concentrations, and may reduce elevated parathyroid hormone (PTH) concentrations and the histologic manifestations of osteitis fibrosa cystica and defective mineralization.

Has been used in children undergoing dialysis†, to increase serum calcium and decrease PTH concentrations.

Secondary Hyperparathyroidism

Management of secondary hyperparathyroidism and resultant metabolic bone disease in patients with moderate to severe chronic renal failure (Cl_cr 15–55 mL/minute, corrected for surface area in children) who do not yet require maintenance dialysis therapy (predialysis patients).

Serum intact PTH (iPTH) concentrations of ≥100 pg/mL are strongly suggestive of secondary hyperparathyroidism.

Hypoparathyroidism and Pseudohypoparathyroidism

Management of hypocalcemia and its clinical manifestations in patients with postsurgical hypoparathyroidism, idiopathic hypoparathyroidism, and pseudohypoparathyroidism.

Nutritional Rickets or Osteomalacia

Has been used to control serum calcium concentrations and treat vitamin D-dependent rickets† or osteomalacia† in a few adult and pediatric patients.

Tetany in Premature Infants

Has been used in the prevention of tetany in vitamin D-deficient premature infants with hypocalcemia†; also has been used in the treatment of hypocalcemic tetany in premature infants†.

Familial Hypophosphatemia

Has been used in conjunction with phosphate supplements in the treatment of bone disorders in adult patients with familial hypophosphatemia† (vitamin D-resistant rickets).

Dosage and Administration

General

• Measure serum calcium concentrations at least twice a week during initial therapy and after subsequent dosage adjustments. Some clinicians recommend measuring serum calcium concentrations at least weekly for the first 12 weeks of therapy and monthly after stabilization of dosage.
• For calcitriol therapy to be effective, patients must have an adequate, but not excessive, daily intake of calcium.

Administration

Calcitriol is administered orally or by IV injection, usually in a single daily dose.

IV Administration

Administer IV by rapid injection through catheter at the end of a period of hemodialysis.

Dosage

Individualize dosage based on nature and severity of patient’s hypocalcemia and/or secondary hyperparathyroidism; maintain serum calcium concentrations at 9–10 mg/dL.

Individualize dosage adjustments based on PTH, serum calcium and phosphorus concentrations.

Administer lowest possible dosage and only increase after careful monitoring of serum calcium concentrations.

Pediatric Patients

Dosing guidelines not established for pediatric patients <1 year of age with hypoparathyroidism or for pediatric patients <6 years of age with pseudohypoparathyroidism.

Hypocalcemia Secondary to Chronic Renal Disease

Patients Undergoing Dialysis

Oral

0.25–2 mcg daily.†

Secondary Hyperparathyroidism

Predialysis Patients (Cl_cr 15–55 mL/minute corrected for surface area)

Oral

<3 years old: Initially, 0.01–0.015 mcg/kg once daily.

≥3 years old: Initially, 0.25 mcg daily.

≥3 years old: May increase if necessary to 0.5 mcg daily.

Hypoparathyroidism and Pseudohypoparathyoidism

Oral

Children ≥1 years old: Initially, 0.25 mcg daily. Since only a limited number of children <6 years of age with pseudohypoparathyroidism have received the drug, dosage recommendations for such children currently do not exist.

If adequate clinical and biochemical responses are not obtained with initial dosage, increase dosage at 2- to 4-week intervals.

If hypercalcemia occurs during titration, withhold dose until normocalcemia ensues; reinstate at a lower dosage. May consider decreasing dietary calcium intake.

Children 1–5 years of age (with hypoparathyroidism) usually require 0.25–0.75 mcg daily.

Most children ≥6 years old: 0.5–2 mcg daily.

Nutritional Rickets or Osteomalacia

Oral

1 mcg daily has been used.†

Tetany in Premature Infants

Prevention of Tetany Associated with Vitamin D Deficiency and Hypocalcemia

Oral

1 mcg daily for first 5 days of life has been used.†

Treatment of Tetany Associated with Hypocalcemia

IV

0.05 mcg/kg daily for 5–12 days has been used.†

Adults

Hypocalcemia Secondary to Chronic Renal Disease

Patients Undergoing Dialysis

Oral

Initially, 0.25 mcg daily. Patients with normal or slightly reduced serum calcium concentrations require 0.25 mcg every other day.

If adequate clinical and biochemical responses are not obtained with initial dosage, increase dosage by 0.25 mcg daily at 4- to 8-week intervals.

Usual dosage: 0.5–1 mcg daily.

If hypercalcemia occurs, discontinue drug immediately until normocalcemia ensues.

IV

Initially, 1 mcg (0.02 mcg/kg) to 2 mcg administered 3 times weekly, approximately every other day; however, initial dosages may range from 0.5–4 mcg 3 times weekly.

If a satisfactory response is not observed, increase the dose given 3 times weekly by 0.5–1 mcg at 2- to 4-week intervals.

If hypercalcemia or a serum calcium × phosphorous (C_a × P) product >70 mg²/ dL² occurs, discontinue drug immediately until these parameters are appropriate. Then reinitiate at a lower dosage.

Adjust dosage of calcitriol according the patient’s PTH concentrations.

Secondary Hyperparathyroidism

Predialysis Patients

Oral

Initially, 0.25 mcg daily.

May increase if necessary to 0.5 mcg daily.

Hypoparathyroidism and Pseudohypoparathyoidism

Oral

Initially, 0.25 mcg daily given in the morning.

If a satisfactory response in biochemical parameters and clinical manifestations is not observed, increase dosage at 2- to 4-week intervals.

Usual dosage: 0.5–2 mcg daily.

Nutritional Rickets or Osteomalacia

Oral

1 mcg daily has been used.†

Familial Hypophosphatemia (Vitamin D-resistant rickets)

Oral

2.1 mcg daily has been used.†

Special Populations

Geriatric Patients

Select dosage with caution (generally starting at the low end of the dosing range) because of age-related decreases in hepatic, renal, and/or cardiac function, and concomitant disease and drug therapy.