What is the protocol for Vitamin D (Cholecalciferol) replacement therapy?

From the Guidelines

Vitamin D replacement should be initiated with a dose of 600-800 IU daily for individuals with deficiency, typically defined as serum 25-hydroxyvitamin D levels below 20 ng/mL, as recommended by the Institute of Medicine 1.

Key Considerations

• The definition of vitamin D deficiency varies, but a commonly used threshold is a 25(OH)D level below 20 ng/mL 1.
• The daily use of vitamin D is recommended to be 600 IU for individuals from 1 to 70 years of age, and 800 IU for individuals 71 and older 1.
• A "safe upper limit" of dietary vitamin D intake is 4000 IU daily, above which the risk of toxicity increases 1.

Treatment Regimens

• For treatment of deficiency, vitamin D3 (cholecalciferol) can be used at a dose of 50,000 IU weekly for 8 weeks, followed by maintenance therapy of 1,000-2,000 IU daily 1.
• Alternatively, daily dosing of 5,000-6,000 IU for 8-12 weeks can be used for repletion 1.
• Maintenance therapy should be continued indefinitely for most patients, especially those with limited sun exposure, darker skin tones, or malabsorption conditions.

Monitoring and Adjustments

• Recheck vitamin D levels after 3-4 months of therapy to ensure adequate replacement, aiming for a target level of 30-50 ng/mL 1.
• Excessive supplementation should be avoided as levels above 100 ng/mL may cause hypercalcemia and other adverse effects 1.

Additional Recommendations

• Calcium supplementation (1,000-1,200 mg daily) should accompany vitamin D replacement to optimize bone health 1.
• Vitamin D is essential for calcium absorption and bone mineralization, and deficiency can lead to osteomalacia in adults and rickets in children, and may have protective effects against various chronic diseases 1.

From the FDA Drug Label

Vitamin D3 50,000 IU is essential for absorption of calcium and necessary for healthy bones and a healthy immune system. INDICATIONS AND USAGE Cholecalciferol Softgel capsule is essential for absorption of calcium and necessary for healthy and strong bones. DIRECTIONS: Take 0ne (1) capsule each week, or as directed by your physician.

Vitamin D replacement can be achieved with Cholecalciferol (Vitamin D3) 50,000 IU softgel capsules, taken once a week, or as directed by a physician.

• The recommended dosage is one capsule per week.
• It is essential to take the capsule with food.
• Patients with certain conditions, such as hypercalcemia, malabsorption syndrome, abnormal sensitivity to the toxic effects of vitamin D, and hypervitaminosis D, should not take this supplement 2.

From the Research

Vitamin D Replacement Therapy

• The treatment of vitamin D deficiency varies, with recommendations ranging from calciferol 800 IU per day to loading doses of vitamin D followed by maintenance therapy of up to 2000 IU per day 3.
• A study found that the average daily dose of vitamin D resulting in any increase in serum 25-hydroxyvitamin D level was 4707 IU/day, with significant factors affecting the change in serum concentrations including starting serum concentration, body mass index, age, and serum albumin concentration 4.
• The recommended daily allowance for vitamin D is often inadequate for correcting low serum concentrations, with about 5000 IU vitamin D3/day usually needed to correct deficiency, and a maintenance dose of ≥2000 IU/day 4.

Forms of Vitamin D

• Cholecalciferol is the major form of vitamin D that nurtures the body, while ergocalciferol is primarily a synthetic and less stable product 5.
• Calcidiol and calcitriol are not nutrients and are not pertinent to food fortification or dietary supplementation 5.
• Cholecalciferol is more effective at raising serum 25-hydroxyvitamin D in non-dialysis-dependent CKD patients while active therapy is ongoing, compared to ergocalciferol 6.

Dosing and Toxicity

• High-dose ergocalciferol is one common replenishment therapy for vitamin D deficiency, but pharmacists should be aware of appropriate replenishment therapies and correct dosing of different vitamin D products 7.
• Vitamin D toxicity can occur with incorrect dosing, and pharmacists should be familiar with possible toxic effects, particularly as public awareness of benefits continues to increase 7.
• A predictive equation can be used to guide vitamin D replacement dose in patients, taking into account factors such as starting serum concentration, age, body mass index, and serum albumin concentration 4.