What form of Vitamin D should be initiated in my patient?

From the Guidelines

I strongly recommend initiating vitamin D3 (cholecalciferol) supplementation in your patient, as it is more effective in raising and maintaining serum 25(OH)D levels compared to vitamin D2 (ergocalciferol). When deciding on the form of vitamin D supplementation, it is essential to consider the differences in metabolism and efficacy between vitamin D2 and D3. According to the study by the NCCN task force report on bone health in cancer care 1, vitamin D3 could be more effective in raising 25(OH)D concentrations and maintaining those levels for a longer time when longer dosing intervals are employed. The following key points should be considered when initiating vitamin D supplementation:

• The goal of supplementation is to bring serum 25(OH)D levels to 30 ng/ml (75 nmol/L) or higher for optimal bone health 1.
• For patients with serum 25(OH)D levels below 30 ng/mL, a common regimen is prescription vitamin D (ergocalciferol) 50,000 IU weekly for 8 weeks, followed by a recheck of the serum 25(OH)D level, with subsequent dosing based on the results 1.
• For patients with 25(OH)D levels between 20 and 30, an alternative is adding 1000 IU over the counter vitamin D2 or D3 per day to the patient's current intake and rechecking the level in 3 months 1.
• Vitamin D toxicity is uncommon but may occur with daily doses of more than 50,000 IU per day that produce 25(OH)D levels larger than 150 ng/mL 1.
• Current expert opinion recommends 800 to 1000 IU of vitamin D daily for adults older than age 50, and the NCCN Bone Health in Cancer Care Task Force also recommends these ranges for younger patients at risk for cancer treatment–associated bone loss 1.

From the FDA Drug Label

Warnings WARNINGS: Vitamin D3 is a high Potency dietary supplement. Do not exceed recommended dosage. Health Claims DIETARY SUPPLEMENT Vitamin D3 50,000 IU is essential for absorption of calcium and necessary for healthy bones and a healthy immune system.

The patient should be initiated on Vitamin D3 (cholecalciferol). Key considerations include:

• Dosage: do not exceed the recommended dosage
• Contraindications: not recommended for children, pregnant or lactating women, or individuals with liver disease
• Interactions: individuals taking thiazide diuretics may be at greater risk of toxicity 2
• Form: 50,000 IU is available as a dietary supplement 2

From the Research

Vitamin D Supplementation

The form of Vitamin D to be initiated in a patient depends on various factors, including the patient's risk of deficiency, age, and health status.

• Cholecalciferol (Vitamin D3) is considered more effective than ergocalciferol (Vitamin D2) in treating nutritional vitamin D deficiency, especially in patients with chronic kidney disease (CKD) 3.
• Daily doses of 7000 IU or intermittent doses of 30,000 IU/week of cholecalciferol may be considered for patients at high risk of vitamin D deficiency, such as those with obesity, liver disease, or malabsorption syndromes 4.
• For patients with documented vitamin D deficiency, a cumulative dose of at least 600,000 IU administered over several weeks may be necessary to replenish vitamin D stores 5.
• The recommended daily dose of vitamin D3 to achieve a calcidiol level of at least 30 ng/mL is 1000-3000 IU/d, which may be necessary for kidney transplant patients 6.

Dosage Considerations

When determining the appropriate dosage of vitamin D, several factors should be considered, including:

• Starting serum concentration of 25-hydroxyvitamin D
• Body mass index (BMI)
• Age
• Serum albumin concentration
• A predictive equation can be used to estimate the required dose of vitamin D, taking into account these factors 7.
• The equation is: Dose = [(8.52 - Desired change in serum 25-hydroxyvitamin D level) + (0.074 × Age) - (0.20 × BMI) + (1.74 × Albumin concentration) - (0.62 × Starting serum 25-hydroxyvitamin D concentration)]/(-0.002) 7.

Patient-Specific Considerations

The decision to initiate vitamin D supplementation should be based on individual patient needs and health status.

• Patients with increased risk of vitamin D deficiency, such as those with obesity, liver disease, or malabsorption syndromes, may require higher doses of vitamin D 4.
• Kidney transplant patients may require vitamin D3 supplementation to achieve a calcidiol level of at least 30 ng/mL 6.
• The dose of vitamin D should be adjusted based on the patient's response to treatment and serum 25-hydroxyvitamin D levels 5, 7.