What is the recommended dose of calcitriol (Vitamin D3) for adults with hypoparathyroidism, osteoporosis, or chronic kidney disease?

Calcitriol Dosing for Adults

Chronic Kidney Disease (Non-Dialysis)

For adults with CKD stages 3-4 (GFR 15-60 mL/min/1.73 m²), initiate calcitriol at 0.25 mcg/day orally when intact PTH exceeds 70 pg/mL, with the goal of maintaining PTH within target range for the CKD stage. 1

Initial Dosing Strategy

• Start at 0.25 mcg/day orally for most patients 1, 2
• Occasionally increase to 0.5 mcg/day based on PTH response 1
• For pediatric patients under 3 years: 10-15 ng/kg/day 2

Critical Prerequisites Before Starting

• Serum corrected calcium must be <9.5 mg/dL (absolute requirement) 1
• Serum phosphorus must be <4.6 mg/dL (absolute requirement) 1
• Correct nutritional vitamin D deficiency first with ergocalciferol or cholecalciferol if 25(OH)D <30 ng/mL 1
  • Calcitriol does not raise 25-hydroxyvitamin D levels and should never be used to treat nutritional vitamin D deficiency 1

Monitoring Schedule

• First month: Check calcium and phosphorus every 2 weeks 3, 1
• Months 1-3: Check calcium and phosphorus monthly 3
• After 3 months: Check calcium and phosphorus every 3 months 3
• PTH monitoring: Every 3 months for first 6 months, then every 3 months thereafter 3

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Dialysis Patients (Hemodialysis or Peritoneal Dialysis)

For dialysis patients with intact PTH >300 pg/mL, initiate calcitriol with the target of reducing PTH to 150-300 pg/mL, using intravenous administration three times weekly as it is superior to daily oral dosing. 3, 1

Dosing Options

• Oral: 0.25 mcg/day initially, with most patients responding to 0.5-1.0 mcg/day 2, 4
• Intravenous (preferred): 0.5-1.0 mcg three times weekly 3, 1
  • IV calcitriol is more effective than daily oral calcitriol for PTH suppression 3
• Peritoneal dialysis: 0.5-1.0 mcg orally 2-3 times weekly, or 0.25 mcg daily 3

Severe Hyperparathyroidism (PTH >500-600 pg/mL)

• May require 2-3 mcg three times weekly IV 1
• Adjust based on PTH response 1

Dose Adjustments During Treatment

• If PTH falls below 150 pg/mL: Hold calcitriol until PTH rises above 150 pg/mL, then resume at half the previous dose 3, 1
• If calcium exceeds 9.5 mg/dL: Hold calcitriol until calcium <9.5 mg/dL, then resume at half dose 3, 1
• If phosphorus rises >4.6 mg/dL: Hold calcitriol, initiate or increase phosphate binder, then resume prior dose once phosphorus <4.6 mg/dL 3

Monitoring for Dialysis Patients

• First month: Calcium and phosphorus every 2 weeks 3
• Ongoing: Calcium and phosphorus monthly 3
• PTH: Monthly for 3 months, then every 3 months 3

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Hypoparathyroidism

For adults with hypoparathyroidism, initiate calcitriol at 0.25 mcg/day in the morning, with most patients responding to 0.5-2.0 mcg daily. 2

Dosing Guidelines

• Initial dose: 0.25 mcg/day 2
• Typical maintenance range: 0.5-2.0 mcg daily for adults and children ≥6 years 2
• Pediatric (ages 1-5 years): 0.25-0.75 mcg daily 2
• Increase dose at 2-4 week intervals if biochemical parameters do not improve 2

Special Considerations

• Malabsorption may occur in hypoparathyroidism patients, requiring larger doses 2
• Monitor serum calcium at least twice weekly during titration 2
• Check serum calcium, phosphorus, and 24-hour urinary calcium periodically 2

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Osteoporosis

Calcitriol is not a first-line treatment for osteoporosis in the general population; ensure adequate nutritional vitamin D (800 IU daily) and calcium supplementation instead. 3

Context for Use

• Nutritional vitamin D (ergocalciferol or cholecalciferol) at 800 IU/day with calcium supplementation reduces hip fracture risk by 43% 3
• Calcitriol should be reserved for specific conditions like CKD-related bone disease, not routine osteoporosis 3

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Critical Safety Parameters Across All Indications

Calcium Supplementation

• Ensure 600-1200 mg elemental calcium daily from diet or supplements 2
• Total calcium intake should not exceed 2000 mg/day 5
• Some patients on calcitriol may require lower calcium or no supplementation if hypercalcemia develops 2

Immediate Discontinuation Required If:

• Serum calcium exceeds 10.2-10.5 mg/dL 1, 5
• Hypercalcemia develops (hold until normocalcemia, then resume at half dose) 3, 2

Common Pitfalls to Avoid

• Never use calcitriol to treat nutritional vitamin D deficiency - it will not raise 25(OH)D levels 1
• Always correct nutritional vitamin D deficiency first before starting calcitriol 1
• Do not start calcitriol if calcium >9.5 mg/dL or phosphorus >4.6 mg/dL in CKD patients 1
• Avoid over-suppressing PTH in dialysis patients - target is 150-300 pg/mL, not complete suppression 3, 1