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Calcitriol Dosage

Applies to the following strength(s): 0.25 mcg ; 0.5 mcg ; 1 mcg/mL ; 2 mcg/mL

The information at Drugs.com is not a substitute for medical advice. Always consult your doctor or pharmacist.

Usual Adult Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Hypocalcemia

Oral:
Initial dose: 0.25 mcg orally once a day
Maintenance dose: 0.5 to 1 mcg orally once a day

Intravenous:
Initial dose: 1 to 2 mcg (0.02 mcg/kg) IV three times weekly (approximately every other day)
Maintenance dose: 0.5 to 4 mcg three times weekly

Comments:
-Effective therapy requires patients to receive an adequate and appropriate daily intake of calcium (minimum 600 mg daily).
-The RDA for calcium for adults is 1000 to 1300 mg.
-To ensure adequate calcium, prescribe a calcium supplement or instruct the patient in proper dietary measures.
-Because of improved calcium absorption from the gastrointestinal tract, some patients may be maintained on a lower calcium intake; those who tend toward hypercalcemia may need low calcium doses or no supplementation at all.
-During titration, obtain serum calcium and phosphorus levels at least twice weekly.
-Start at the lowest possible dose.
-Treatment may normalize plasma ionized calcium in some uremic patients, but fail to suppress parathyroid function; in these patients the drug may be useful for controlling calcium, but may not be adequate treatment for hyperparathyroidism.

Uses: Management of hypocalcemia and the resultant metabolic bone disease in patients undergoing chronic renal dialysis. Enhances calcium absorption, reduces serum alkaline phosphatase, and may reduce elevated parathyroid hormone levels and the histological manifestations of osteitis fibrosa cystica and defective mineralization. Reduction of parathyroid hormone results in an improvement in renal osteodystrophy.

Usual Adult Dose for Renal Osteodystrophy

Oral:
Initial dose: 0.25 mcg orally once a day
Maintenance dose: 0.5 to 1 mcg orally once a day

Intravenous:
Initial dose: 1 to 2 mcg (0.02 mcg/kg) IV three times weekly (approximately every other day)
Maintenance dose: 0.5 to 4 mcg three times weekly

Comments:
-Effective therapy requires patients to receive an adequate and appropriate daily intake of calcium (minimum 600 mg daily).
-The RDA for calcium for adults is 1000 to 1300 mg.
-To ensure adequate calcium, prescribe a calcium supplement or instruct the patient in proper dietary measures.
-Because of improved calcium absorption from the gastrointestinal tract, some patients may be maintained on a lower calcium intake; those who tend toward hypercalcemia may need low calcium doses or no supplementation at all.
-During titration, obtain serum calcium and phosphorus levels at least twice weekly.
-Start at the lowest possible dose.
-Treatment may normalize plasma ionized calcium in some uremic patients, but fail to suppress parathyroid function; in these patients the drug may be useful for controlling calcium, but may not be adequate treatment for hyperparathyroidism.

Uses: Management of hypocalcemia and the resultant metabolic bone disease in patients undergoing chronic renal dialysis. Enhances calcium absorption, reduces serum alkaline phosphatase, and may reduce elevated parathyroid hormone levels and the histological manifestations of osteitis fibrosa cystica and defective mineralization. Reduction of parathyroid hormone results in an improvement in renal osteodystrophy.

Usual Adult Dose for Hypoparathyroidism

Initial dose: 0.25 mcg orally once a day in the morning
Maintenance dose: 0.5 mcg to 2 mcg orally once a day

Comments:
-Obtain serum calcium at least twice weekly during dose titration.
-Monitor serum calcium, phosphorus, and 24-hour urinary calcium periodically.
-Malabsorption is seen occasionally in hypoparathyroidism and may require a larger dose of this drug.

Uses: Management of hypocalcemia and its clinical manifestations in postsurgical hypoparathyroidism, idiopathic hypoparathyroidism, and pseudohypoparathyroidism

Usual Adult Dose for Secondary Hyperparathyroidism

Initial dose: 0.25 mcg orally once a day
-May increase to 0.5 mcg orally once a day if needed

Comments:
-Serum iPTH level of 100 pg/mL or higher is strongly suggestive of secondary hyperparathyroidism.

Use: Management of secondary hyperparathyroidism and resultant metabolic bone disease in moderate to severe chronic renal failure (creatinine clearance 15 to 55 mL/min) not yet on dialysis.

Usual Pediatric Dose for Hypoparathyroidism

1 to 5 years:
Initial dose: 0.25 mcg, orally, once a day (in the morning)
Maintenance dose: 0.25 mcg to 0.75 mcg, orally, once a day (in the morning)

6 years and older:
Initial dose: 0.25 mcg, orally, once a day (in the morning)
Maintenance dose: 0.5 mcg to 2 mcg, orally, once a day (in the morning)

Comments:
-Obtain serum calcium at least twice weekly during dose titration.
-Monitor serum calcium, phosphorus, and 24-hour urinary calcium periodically.
-Malabsorption is seen occasionally in hypoparathyroidism and may require a larger dose of this drug.

Uses: Management of hypocalcemia and its clinical manifestations in postsurgical hypoparathyroidism, idiopathic hypoparathyroidism, and pseudohypoparathyroidism

Usual Pediatric Dose for Hypocalcemia

Oral:
Initial dose: 0.25 mcg, orally, once a day
Maintenance dose: 0.5 to 1 mcg, orally, once a day

Intravenous:
Initial dose: 1 (0.02 mcg/kg) to 2 mcg, IV, three times weekly (approximately every other day)
Maintenance dose: 0.5 to 4 mcg three times weekly

Comments:
-Effective therapy requires patients to receive an adequate and appropriate daily intake of calcium (minimum 600 mg daily).
-The RDA for calcium for children varies from 200 to 1300 mg.
-To ensure adequate calcium, prescribe a calcium supplement or instruct the patient in proper dietary measures.
-Because of improved calcium absorption from the gastrointestinal tract, some patients may be maintained on a lower calcium intake; those who tend toward hypercalcemia may need low calcium doses or no supplementation at all.
-During titration, obtain serum calcium and phosphorus levels at least twice weekly.
-Start at the lowest possible dose.
-Treatment may normalize plasma ionized calcium in some uremic patients, but fail to suppress parathyroid function; in these patients the drug may be useful for controlling calcium, but may not be adequate treatment for hyperparathyroidism.

Uses: Management of hypocalcemia and the resultant metabolic bone disease in patients undergoing chronic renal dialysis. Enhances calcium absorption, reduces serum alkaline phosphatase, and may reduce elevated parathyroid hormone levels and the histological manifestations of osteitis fibrosa cystica and defective mineralization. Reduction of parathyroid hormone results in an improvement in renal osteodystrophy.

Usual Pediatric Dose for Secondary Hyperparathyroidism

Under 3 years:
Initial dose: 10 to 15 ng/kg/day orally

3 years and older:
Initial dose: 0.25 mcg orally once a day
-May increase to 0.5 mcg orally once a day if needed

Comments:
-Creatinine clearance value must be corrected for a surface area of 1.73 square meters in children.
-Serum iPTH level of 100 pg/mL or higher is strongly suggestive of secondary hyperparathyroidism.

Use: Management of secondary hyperparathyroidism and resultant metabolic bone disease in moderate to severe chronic renal failure (creatinine clearance 15 to 55 mL/min) not yet on dialysis.

Renal Dose Adjustments

Secondary hyperparathyroidism: See Usual Adult Dose
Hypocalcemia: See Usual Adult dose
Hypoparathyroidism: Data not available

Liver Dose Adjustments

Data not available

Dose Adjustments

Hypercalcemia
-Discontinue this drug immediately if hypercalcemia develops.
-Monitor serum calcium and phosphate daily during periods of hypercalcemia.
-When serum calcium normalizes, treatment can continue at an oral dose 0.25 mcg lower than the previous dose.
-Careful consideration should be given to lowering the dietary calcium intake.


Hypocalcemia - Intravenous dose adjustments:
-If satisfactory response is not observed, increase IV dose by 0.5 to 1 mcg at 2 to 4 week intervals
-Dose reductions may be needed as parathyroid hormone (PTH) levels decrease in response to therapy.
If PTH is:
-the same or increasing: increase dose
-decreasing by less than 30%: increase dose
-decreasing more than 30% but less than 60%: maintain dose
-decreasing more than 60%: decrease dose
-one and a half to three times the upper limit of normal: maintain dose

Hypocalcemia - Oral dose adjustments:
-If satisfactory response is not observed, increase oral dose by 0.25 mcg per day at 4 to 8 week intervals
-Patients with normal or only slightly reduced serum calcium may respond to 0.25 mcg every other day

Hypoparathyroidism
-If satisfactory response is not observed, increase oral dose at 2 to 4 week intervals
-Malabsorption is seen occasionally in hypoparathyroidism and may require a larger dose of this drug.

Dialysis

Hypocalcemia: See Usual Adult Dose

Other Comments

Storage requirements:
-Store at controlled room temperature; protect from light

Monitoring:
-Monitor serum calcium twice weekly early in therapy and during dose adjustments.
-Discontinue this drug immediately if hypercalcemia develops.
-Monitor serum calcium and phosphate daily during periods of hypercalcemia.
-When serum calcium normalizes, treatment can continue at a lower dose.
-In dialysis patients, monitor serum calcium, phosphorous, magnesium, and alkaline phosphatase periodically.
-In hypoparathyroid patients, monitor serum calcium, phosphorous, and 24 hour urinary calcium periodically.
-In predialysis patients, determine serum calcium, phosphorous, alkaline phosphatase, creatinine, and intact parathyroid hormone (iPTH) at baseline, then monthly for 6 months, then periodically.
-Monitor iPTH every 3 to 4 months.
-During titration, monitor serum calcium twice weekly.

Patient advice:
-Inform patients/caregivers about the importance of compliance with dosing, adherence to diet and calcium supplementation instructions, and avoidance of unapproved nonprescription medications.
-Inform patients of the symptoms of hypercalcemia.
-Therapy effectiveness requires adequate daily intake of calcium, minimum 600 mg daily; US RDA for calcium for adults is 800 to 1200 mg.
-Maintain adequate fluid intake to avoid dehydration.

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