What is the treatment for vitamin D deficiency?

Treatment for Vitamin D Deficiency

For vitamin D deficiency, treatment should be tailored based on severity, with 50,000 IU weekly for 4-8 weeks for levels 5-15 ng/mL, followed by maintenance therapy of 800-1,000 IU/day. 1

Diagnosis and Classification

• Vitamin D deficiency is defined as serum 25-hydroxyvitamin D levels:
  • Severe deficiency: <5 ng/mL
  • Mild deficiency: 5-15 ng/mL
  • Insufficiency: 16-30 ng/mL 1
• Common symptoms include symmetric low back pain, proximal muscle weakness, muscle aches, and throbbing bone pain over the sternum or tibia 2

Treatment Algorithm Based on Severity

For Mild Deficiency (15-20 ng/mL)

• Supplement with 800-1,000 IU vitamin D daily 1
• Regular monitoring of serum 25(OH)D, calcium, and phosphorus during supplementation
• Follow-up testing 3-4 months after initiating therapy 1

For Moderate Deficiency (5-15 ng/mL)

• Prescribe 50,000 IU vitamin D weekly for 4-8 weeks 1, 2
• After normalization, transition to maintenance dose of 800-1,000 IU daily 1, 2
• Ensure adequate calcium intake (1000-1500 mg daily) alongside vitamin D supplementation 1

For Severe Deficiency (<5 ng/mL)

• Individualized treatment under close monitoring 1
• In cases of documented severe deficiency, a cumulative dose of at least 600,000 IU administered over several weeks appears necessary to replenish vitamin D stores 3
• Caution: Single large doses of 300,000-500,000 IU should be avoided due to risk of toxicity 1, 3

Special Population Considerations

Higher Doses Required For:

• Dark-skinned or veiled individuals: 800 IU/day
• Adults ≥65 years: 800 IU/day
• Institutionalized individuals: 800 IU/day
• Patients with obesity: 2-3 times higher doses (up to 7,000 IU daily)
• Patients with malabsorption syndromes: higher doses or weekly regimens
• Patients with liver disease: higher doses due to impaired hepatic 25-hydroxylation 1

Chronic Kidney Disease Patients

• For CKD stages 3-4 with elevated PTH despite nutritional vitamin D repletion:
  • Initiate active vitamin D analog when serum 25(OH)D levels >30 ng/mL
  • Corrected total calcium <9.5 mg/dL
  • Serum phosphorus <4.6 mg/dL 1

Safety Monitoring and Precautions

• Safe upper limit for vitamin D supplementation is generally 4,000 IU daily for adults 1, 4
• Monitor for complications of vitamin D therapy:
  • Hypercalcemia
  • Hyperphosphatemia
  • Over-suppression of PTH 1, 4
• Vitamin D toxicity signs include:
  • Anorexia, nausea, weakness, constipation
  • Polyuria, polydipsia, hypercalciuria
  • Widespread calcification of soft tissues
  • Bone demineralization 4

Maintenance Therapy

• After normalization of vitamin D levels:
  • Adults 19-70 years: 600-800 IU daily
  • Adults >70 years: 800 IU daily 1, 2
• Some recent evidence suggests that 2,000 IU daily may be optimal for maintaining levels above 30 ng/mL in >90% of adults 5

Important Clinical Considerations

• Therapeutic dosage should be readjusted once clinical improvement occurs 4
• Mineral oil interferes with absorption of vitamin D preparations 4
• Thiazide diuretics may cause hypercalcemia in patients treated with vitamin D 4
• Elderly patients may have attenuated absorption of oral vitamin D; consider starting at lower end of dosing range 4
• Regular monitoring is essential, with follow-up testing 3-4 months after initiating therapy 1