Ergocalciferol (Vitamin D2) Dosing for Vitamin D Deficiency Treatment
For treating vitamin D deficiency, ergocalciferol (Vitamin D2) 50,000 IU should be administered once weekly for 8-12 weeks, followed by monthly maintenance dosing of 50,000 IU to maintain adequate vitamin D levels. 1
Dosing Based on Deficiency Severity
- Severe deficiency (<10 ng/mL): 50,000 IU weekly for 12 weeks, followed by monthly maintenance dosing 1
- Mild to moderate deficiency (10-20 ng/mL): 50,000 IU weekly for 8 weeks, followed by monthly maintenance 1, 2
- Insufficiency (20-30 ng/mL): 50,000 IU every other week for 12 weeks 2, 3
- Maintenance therapy: After achieving target levels (≥30 ng/mL), continue with 50,000 IU monthly 1
Administration Considerations
- Ergocalciferol capsules should be taken with food to enhance absorption 2
- Monthly dosing of 50,000 IU achieves the equivalent of approximately 1,600 IU daily 1, 3
- Ensure adequate calcium intake (1,000-1,500 mg daily) alongside vitamin D supplementation 2, 3
- For convenience in adults with normal kidney function, one 50,000 IU capsule monthly is appropriate for maintenance therapy 1
Monitoring Recommendations
- Check serum 25(OH)D levels after 3-6 months of therapy to ensure adequate response 2, 3
- Target serum 25(OH)D level should be at least 30 ng/mL for optimal bone health and anti-fracture efficacy 2
- Monitor serum calcium if using high doses for extended periods 1
- Development of hypercalcemia would indicate excessive dosing 1
Special Populations
- Chronic kidney disease patients: Ergocalciferol is preferred over cholecalciferol for patients with CKD 1
- Elderly patients (≥65 years): May require higher maintenance doses due to decreased skin synthesis 2
- Obese patients: May require higher doses (up to 50,000 IU weekly) for maintenance due to sequestration in adipose tissue 4
- Patients with malabsorption: May require higher doses or more frequent administration 2, 4
Safety Considerations
- Ergocalciferol doses of up to 10,000 IU daily have been given to patients with advanced CKD for over a year without evidence of toxicity 1
- Vitamin D toxicity is rare but can occur with prolonged high doses (typically >10,000 IU daily) 2
- Calcitriol or other synthetic active vitamin D analogs should not be used to treat vitamin D deficiency 1, 3
- Case reports show lack of toxicity even with extremely high doses (150,000 IU daily for years), though such doses are not recommended 5
Efficacy of Treatment Regimens
- Regimens containing at least 600,000 IU of ergocalciferol total dose are most effective in achieving vitamin D sufficiency 6
- The 50,000 IU three times weekly for 6 weeks regimen achieved sufficiency in 82% of patients in one study 6
- The response to vitamin D supplementation varies between individuals due to genetic factors and body composition 2, 3
Common Pitfalls to Avoid
- Not ensuring adequate duration of treatment (minimum 8 weeks for loading dose) 2, 6
- Failing to transition to maintenance therapy after initial repletion 1, 2
- Not accounting for individual variability in response to supplementation 2, 3
- Using single annual high doses which may lead to adverse outcomes 2