What is the recommended treatment for vitamin D deficiency?

Treatment of Vitamin D Deficiency

For vitamin D deficiency, the recommended treatment is 50,000 IU of vitamin D once weekly for 8 weeks, followed by a maintenance dose of 800-2,000 IU daily. 1

Diagnosis and Classification

• Vitamin D deficiency is defined as serum 25(OH)D levels:
  • Deficiency: <20 ng/mL (50 nmol/L)
  • Insufficiency: 20-30 ng/mL (50-75 nmol/L)
  • Optimal: 30-80 ng/mL (75-200 nmol/L) 1

Treatment Protocol

Initial Repletion Phase

• For documented vitamin D deficiency:
  • Preferred regimen: 50,000 IU of vitamin D weekly for 8 weeks 1
  • Alternative for severe deficiency (<10 ng/mL): A cumulative dose of at least 600,000 IU administered over several weeks 2
  • Avoid single large doses of 300,000-500,000 IU as they may be inefficient or harmful 1, 2

Maintenance Phase

• After repletion, transition to maintenance dose:
  • General population: 800-2,000 IU daily 1, 3
  • Adults up to age 70: 600 IU daily minimum
  • Adults over 70: 800 IU daily minimum 1
  • Higher-risk individuals may require 1,500-2,000 IU daily 1

Special Populations

Chronic Kidney Disease

• For CKD with GFR 20-60 mL/min/1.73m²:
  • Ergocalciferol (vitamin D2) is recommended
  • For severe deficiency: 50,000 IU weekly for 12 weeks, then monthly 4
  • Monthly maintenance: 50,000 IU (equivalent to approximately 1,600 IU daily) 4

Higher Dose Requirements

• Higher doses may be needed for:
  • Obesity (BMI >30)
  • Malabsorption syndromes
  • Medications affecting vitamin D metabolism
  • Institutionalized or elderly individuals (≥65 years): 800 IU/day minimum 1

Monitoring

• Check vitamin D levels after 3 months of supplementation 1
• For intermittent dosing regimens, measure levels just before the next scheduled dose 1
• Adjust maintenance dose based on follow-up levels
• Target range: 30-80 ng/mL (75-200 nmol/L) 1

Form of Vitamin D

• Vitamin D3 (cholecalciferol) is preferred over vitamin D2 (ergocalciferol) when available due to its longer-lasting effects 1
• Exception: In CKD patients, ergocalciferol may be preferred 4

Safety Considerations

• Safe upper limit for most adults: 4,000 IU daily 1
• Higher-risk patients may safely take up to 10,000 IU daily under medical supervision 1
• Monitor for signs of toxicity with high doses:
  • Hypercalcemia (typically occurs at levels >150 ng/mL)
  • Symptoms include anorexia, nausea, weakness, constipation 5
  • Renal complications: polyuria, hypercalciuria, nephrocalcinosis 5

Common Pitfalls

1. Underdosing: Standard commercial enteral/parenteral products often contain less than the minimum recommended 600-800 IU for healthy adults 4

2. Inadequate monitoring: Failure to check vitamin D levels after 3-6 months can lead to continued deficiency or potential toxicity 4, 1

3. Ignoring comorbidities: Patients with obesity may need higher doses (approximately 5,000 IU/day) to correct deficiency 6

4. Using annual high doses: Daily, weekly, or monthly dosing is preferred over annual high-dose regimens, which may lead to adverse outcomes 1

5. Overlooking inflammation: Plasma levels of vitamin D are significantly reduced during inflammation (CRP>40 mg/L), complicating interpretation 4