What is the recommended treatment for vitamin D deficiency?

Treatment for Vitamin D Deficiency

For vitamin D deficiency (<20 ng/mL), the recommended treatment is ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3) 50,000 IU once weekly for 8-12 weeks, followed by maintenance therapy of 800-2,000 IU daily. 1

Initial Assessment and Diagnosis

• Vitamin D deficiency is defined as serum 25-hydroxyvitamin D [25(OH)D] levels below 20 ng/mL, while insufficiency is defined as levels between 20-30 ng/mL 1
• Severe vitamin D deficiency is defined as levels below 10-12 ng/mL, which significantly increases risk for osteomalacia and nutritional rickets 1, 2
• Measurement of 25(OH)D levels should be performed before initiating treatment to establish baseline status 1

Treatment Protocol Based on Deficiency Severity

For Vitamin D Deficiency (<20 ng/mL):

• Initial loading dose: Ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3) 50,000 IU once weekly for 8-12 weeks 1, 3
• For severe deficiency (<10 ng/mL): 50,000 IU weekly for 12 weeks is recommended 2

For Vitamin D Insufficiency (20-30 ng/mL):

• Add 1,000 IU vitamin D daily to current intake and recheck levels in 3 months 1

Maintenance Therapy:

• After achieving target levels (≥30 ng/mL), transition to maintenance therapy with 800-2,000 IU daily or 50,000 IU monthly 1, 3
• For adults over 60 years, at least 800 IU daily is recommended, while for younger adults 400-1,000 IU daily is typically sufficient 1

Monitoring and Follow-up

• Follow-up vitamin D levels should be measured after 3-6 months of treatment to ensure adequate dosing 1, 2
• If using an intermittent regimen (weekly, monthly), measurement should be performed just prior to the next scheduled dose 1
• Monitor serum calcium and phosphorus levels at least every 3 months during treatment 2
• If serum corrected total calcium exceeds 10.2 mg/dL (2.54 mmol/L), discontinue vitamin D therapy 2

Special Populations and Considerations

• For patients with malabsorption syndromes or those not responding to oral supplementation, parenteral vitamin D may be necessary (typically as IM injection of 50,000 IU) 1
• For patients with chronic kidney disease (CKD), vitamin D supplementation is particularly important as kidney disease is a major risk factor for deficiency 1
• Adequate dietary calcium intake is necessary for optimal response to vitamin D therapy 4
• For obese patients, higher doses may be required due to sequestration of vitamin D in adipose tissue 5

Practical Dosing Options

• Daily dosing is physiologic, but intermittent dosing (weekly or monthly) can have similar effects on 25(OH)D concentration 1
• For convenience, a monthly dose of 50,000 IU can achieve the equivalent of approximately 1,600 IU daily 1
• Cholecalciferol (D3) appears to have higher bioefficacy than ergocalciferol (D2), especially for maintaining 25(OH)D levels when using longer dosing intervals 1, 6

Safety Considerations

• Daily doses up to 4,000 IU are generally considered safe for adults 1
• Toxicity is rare but can occur with prolonged high doses (typically >10,000 IU daily) and may cause hypercalcemia, hypercalciuria, and renal issues 1
• Single very large doses (>300,000 IU) should be avoided as they may be inefficient or potentially harmful 1, 2
• The expert panel agreed on an upper safety limit for 25(OH)D of 100 ng/mL 1