Treatment for Vitamin D Deficiency
For vitamin D deficiency (<20 ng/mL), the recommended treatment is oral ergocalciferol (vitamin D2) 50,000 IU once weekly for 8-12 weeks, followed by maintenance therapy of 800-1000 IU daily. 1
Diagnosis and Classification
- Vitamin D status is determined by measuring serum 25-hydroxyvitamin D [25(OH)D] levels 1
- Deficiency is defined as levels below 20 ng/mL, while insufficiency is defined as levels between 20-30 ng/mL 1
- Severe deficiency is defined as levels below 10-12 ng/mL, which significantly increases risk for osteomalacia and nutritional rickets 1, 2
Treatment Protocol Based on Severity
For Vitamin D Deficiency (<20 ng/mL):
- Initial loading dose: Ergocalciferol (vitamin D2) 50,000 IU once weekly for 8-12 weeks 1, 3
- For severe deficiency (<10 ng/mL): 50,000 IU weekly for 12 weeks followed by monthly maintenance 1
- A cumulative dose of at least 600,000 IU administered over several weeks appears necessary to replenish vitamin D stores 4
- Single large doses (>300,000 IU) should be avoided as they may be inefficient or potentially harmful 1, 4
For Vitamin D Insufficiency (20-30 ng/mL):
- Adding 1000 IU vitamin D daily to current intake and rechecking levels in 3 months 1
- Goal is to achieve 25(OH)D levels of at least 30 ng/mL 5, 1
Maintenance Therapy
- For adults over 60 years: 800 IU daily of vitamin D3 5, 1
- For younger adults: 400-600 IU daily is typically sufficient 5, 1
- For convenience, a monthly dose of 50,000 IU can achieve the equivalent of approximately 1,600 IU daily 5
- Vitamin D3 (cholecalciferol) may be more effective than vitamin D2 (ergocalciferol) for maintaining 25(OH)D levels when using longer dosing intervals 1
Special Populations
Elderly and Institutionalized Individuals:
- Supplementation with 800 IU/day without baseline testing is recommended 5
- Higher maintenance doses may be required due to decreased skin synthesis 1
Chronic Kidney Disease Patients:
- For CKD patients with GFR 20-60 mL/min/1.73m², nutritional vitamin D deficiency can be treated with ergocalciferol or cholecalciferol 5, 1
- In CKD, vitamin D supplementation is particularly important as kidney disease is a major risk factor for deficiency 1
Malabsorption Syndromes:
- Patients with inflammatory bowel disease or prior gastric bypass malabsorb vitamin D and need higher doses 6
- Parenteral vitamin D may be necessary (typically as IM injection of 50,000 IU) for those not responding to oral supplementation 1
Monitoring and Follow-up
- After initiating treatment, follow-up vitamin D levels should be measured after 3-6 months to ensure adequate dosing 5, 1
- The target range for 25(OH)D should be at least 30 ng/mL for optimal health benefit 5, 1
- The expert panel agreed on an upper safety limit for 25(OH)D of 100 ng/mL 5
Safety Considerations
- Daily doses up to 4000 IU are generally considered safe for adults 1, 7
- Toxicity is rare but can occur with prolonged high doses (typically >10,000 IU daily) and may cause hypercalcemia, hypercalciuria, and renal issues 1
- Ensure adequate calcium intake alongside vitamin D supplementation, with a recommended daily intake of 1000-1500 mg 1
Clinical Benefits
- Anti-fall efficacy starts with achieved 25(OH)D levels of at least 24 ng/mL 1
- Anti-fracture efficacy starts with achieved 25(OH)D levels of at least 30 ng/mL 1, 8
- Vitamin D in doses of 800-5000 IU/day improve musculoskeletal health and reduce the rate of fractures and falls in older adults (aged ≥65 years) 4