What is the recommended treatment for vitamin D deficiency?

Recommended Treatment for Vitamin D Deficiency

For vitamin D deficiency, the recommended treatment is ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3) 50,000 IU weekly for 8 weeks, followed by maintenance therapy of 1,000-2,000 IU daily or 50,000 IU monthly. 1

Diagnosis and Treatment Thresholds

• Vitamin D deficiency is defined as serum 25-hydroxyvitamin D level <20 ng/mL (50 nmol/L)
• Vitamin D insufficiency is defined as serum 25-hydroxyvitamin D level of 20-30 ng/mL (50-75 nmol/L)
• Treatment goal: Achieve and maintain serum 25(OH)D levels >30 ng/mL (75 nmol/L) 1

Treatment Protocol

Initial Repletion Phase

• First-line therapy:
  • Ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3) 50,000 IU weekly for 8 weeks 1, 2
  • Cholecalciferol (vitamin D3) may have slight advantages over ergocalciferol when replenishing vitamin D stores 3

Maintenance Phase

After normalization of vitamin D levels:

• Cholecalciferol 1,000-2,000 IU daily OR
• Ergocalciferol 50,000 IU monthly 1, 2

Population-Specific Recommendations

Population	Recommended Daily Dose
Adults up to age 70	600 IU/day
Adults over 70 years	800 IU/day
Dark-skinned or veiled individuals	800 IU/day
Institutionalized individuals	800 IU/day

Monitoring Recommendations

• Check serum calcium, phosphorus, and 25-hydroxyvitamin D levels:
  • Monthly for the first 3 months
  • Every 3 months thereafter 1
• Discontinue vitamin D therapy immediately if:
  • Serum calcium exceeds 10.2 mg/dL
  • Serum phosphorus exceeds 4.6 mg/dL 1

Special Considerations

Chronic Kidney Disease

• For GFR >30 mL/min/1.73m²: Follow general population recommendations (800-1,000 IU daily)
• For GFR <30 mL/min/1.73m²: Either supplementing or not supplementing at doses up to ~4,000 IU daily is reasonable based on clinical judgment 1

Safety and Toxicity

• Safe upper limit for most adults: 4,000 IU daily
• Ultra-high single loading doses (>300,000 IU) are not recommended due to risk of toxicity 1
• Vitamin D toxicity typically occurs at levels above 150 ng/mL 1

Important Precautions

• Evaluate all sources of vitamin D intake (fortified foods, supplements, prescription drugs) 4
• Readjust therapeutic dosage as soon as there is clinical improvement 4
• Monitor closely when using high therapeutic doses, particularly in vitamin D resistant rickets where the therapeutic window is narrow 4
• Mineral oil interferes with vitamin D absorption 4
• Thiazide diuretics may cause hypercalcemia in hypoparathyroid patients treated with ergocalciferol 4

Treatment Efficacy Considerations

• Cholecalciferol (vitamin D3) appears to be more potent than ergocalciferol (vitamin D2), with studies showing it to be approximately 3.2-fold more potent 5
• Calcifediol (25OHD3) results in a more rapid increase in serum 25OHD compared to oral cholecalciferol and may be considered as an alternative, especially in patients with malabsorption 5

Regular monitoring and appropriate dosing adjustments are essential to achieve optimal vitamin D levels while avoiding potential toxicity.