Vitamin D Supplementation for Deficiency in Adults and Children
For vitamin D deficiency, the recommended dosing is 50,000 IU of cholecalciferol weekly for 8-12 weeks followed by maintenance therapy of 800-2,000 IU daily depending on severity and patient characteristics. 1, 2
Treatment Based on Deficiency Severity in Adults
- Severe deficiency (<10-12 ng/mL): 50,000 IU cholecalciferol weekly for 12 weeks, followed by monthly maintenance 1, 2
- Mild-moderate deficiency (10-20 ng/mL): 50,000 IU cholecalciferol weekly for 8 weeks 1, 3
- Insufficiency (20-30 ng/mL): 4,000 IU cholecalciferol daily for 12 weeks or 50,000 IU every other week for 12 weeks 4
Maintenance Therapy for Adults
- After achieving target levels (≥30 ng/mL), maintain with 800-2,000 IU daily or 50,000 IU monthly 1, 4
- For elderly patients (≥65 years), a minimum of 800 IU daily is recommended even without baseline measurement 2
- For patients with obesity, malabsorption, or on medications affecting vitamin D metabolism, higher maintenance doses of 1,500-2,000 IU daily may be required 2, 5
Treatment for Children with Vitamin D Deficiency
- Severe deficiency (<5 ng/mL): 8,000 IU daily for 4 weeks, then 4,000 IU daily for 2 months 6
- Mild deficiency (5-15 ng/mL): 4,000 IU daily for 12 weeks 6
- Insufficiency (16-30 ng/mL): 2,000 IU daily 6
- For infants <12 months, smaller doses are recommended with an upper limit of 1,000 IU/day 6
- After repletion, maintain with 200-1,000 IU daily 6
Practical Dosing Considerations
- Cholecalciferol (vitamin D3) is preferred over ergocalciferol (vitamin D2) due to higher bioefficacy 1, 4
- For convenience, monthly dosing of 50,000 IU achieves the equivalent of approximately 1,600 IU daily 1
- Take vitamin D supplements with food to enhance absorption 7
- Ensure adequate calcium intake (1,000-1,500 mg daily) alongside vitamin D supplementation 1, 4
Monitoring
- Recheck vitamin D levels after 3-6 months of supplementation to ensure adequate response 1, 4
- Target serum 25(OH)D level should be at least 30 ng/mL for optimal bone health and anti-fracture efficacy 1, 4
- Development of hypercalcemia would be evidence of excessive dosing 6
Special Populations
- For patients with chronic kidney disease, vitamin D supplementation is particularly important as kidney disease is a major risk factor for deficiency 1, 4
- For patients requiring enteral nutrition, at least 1,000 IU per day should be provided in 1,500 kcal 1
- For patients requiring parenteral nutrition, at least 200 IU per day should be provided 1
Safety Considerations
- Daily doses up to 4,000 IU are generally considered safe for adults 4, 8
- Vitamin D toxicity is rare but can occur with prolonged high doses (typically >10,000 IU daily) 1, 4
- Single very large doses (>300,000 IU) should be avoided as they may be inefficient or potentially harmful 1
- Calcitriol, alfacalcidol, or other synthetic active vitamin D analogs should not be used to treat 25(OH)D deficiency 6
Common Pitfalls to Avoid
- Not ensuring adequate calcium intake alongside vitamin D supplementation 2
- Using single annual high doses which may lead to adverse outcomes 2
- Not accounting for individual variability in response to supplementation due to genetic factors, body composition, and environmental influences 1, 4
- Not considering higher maintenance doses for patients with obesity, malabsorption, or on medications affecting vitamin D metabolism 5