Vitamin D Supplementation for Low 25(OH)D Levels
For patients with low vitamin D 25 levels, an initial corrective dose of 50,000 IU vitamin D3 once weekly for 8 weeks followed by a maintenance dose of 800-1000 IU daily is recommended. 1
Initial Treatment Based on Severity of Deficiency
- For patients with 25(OH)D levels <30 ng/mL (insufficiency), a large correcting dose should be provided initially, such as 50,000 IU vitamin D3 once weekly for 8 weeks 1
- For severe deficiency with 25(OH)D levels <15 ng/mL, the same regimen of 50,000 IU weekly for 8-12 weeks is recommended 1
- Daily dosing using 7,000 IU/day is an alternative to weekly dosing for patients who prefer daily administration 2
Maintenance Therapy After Initial Correction
- After the initial corrective phase, a maintenance dose of 800-1000 IU/day is recommended for most adults 1, 3
- For patients at higher risk of vitamin D deficiency (obesity, malabsorption, elderly), higher maintenance doses of 1500-2000 IU/day may be required 1, 2
- For patients with chronic kidney disease, maintenance doses of 1000-2000 IU/day are recommended 1
Route of Administration
- Oral supplementation is preferred for most patients 1
- Vitamin D3 (cholecalciferol) is preferred over vitamin D2 (ergocalciferol) for maintenance therapy, especially when using intermittent dosing regimens 1
- For patients with malabsorption, higher doses may be required or alternative routes (IM) may be considered 1
Monitoring
- Measurement of 25(OH)D levels should be performed after at least 3 months of supplementation to allow plateau levels to be reached 1
- For patients on intermittent regimens, measurement should be done just prior to the next scheduled dose 1
- If levels remain insufficient (<30 ng/mL), the maintenance dose should be increased 1, 3
Special Populations
- For obese patients or those with malabsorption syndromes, higher doses may be required (up to 7,000 IU daily or 30,000 IU weekly) 2
- For elderly patients (≥65 years) without specific health problems, 800 IU/day is recommended even without baseline measurement 1
- For patients with chronic kidney disease, vitamin D supplementation should be adjusted based on severity of deficiency 1
Safety Considerations
- Vitamin D toxicity is rare but can occur with prolonged high doses 1, 4
- Daily doses up to 4,000-5,000 IU appear safe for most adults 4, 5
- Single annual high doses (500,000 IU) should be avoided as they may lead to adverse outcomes 1
- Monitoring calcium levels is recommended when using high-dose supplementation regimens 4, 6
Common Pitfalls to Avoid
- Failing to provide an adequate loading dose for patients with deficiency, which delays normalization of levels 5, 7
- Using vitamin D2 instead of vitamin D3 for intermittent dosing regimens, as D3 maintains serum levels for longer periods 1
- Not considering factors that affect vitamin D metabolism such as obesity, age, and albumin levels when determining dosage 5
- Not ensuring adequate calcium intake alongside vitamin D supplementation 3