What is the recommended treatment for vitamin D (Vitamin D) deficiency?

Treatment of Vitamin D Deficiency

For vitamin D deficiency (25(OH)D <20 ng/mL), treat with ergocalciferol or cholecalciferol 50,000 IU once weekly for 8-12 weeks, followed by maintenance therapy of 1,500-2,000 IU daily, with cholecalciferol (D3) strongly preferred over ergocalciferol (D2) due to superior bioavailability and longer-lasting serum levels. 1, 2

Diagnostic Thresholds

• Deficiency is defined as serum 25(OH)D <20 ng/mL and requires treatment 1, 2
• Severe deficiency is defined as 25(OH)D <10-12 ng/mL, which significantly increases risk for osteomalacia in adults and rickets in children 1, 3
• Insufficiency (20-30 ng/mL) should be treated in patients with osteoporosis, fracture risk, falls, or elderly status 2

Loading Phase Protocol

• Administer 50,000 IU once weekly for 8-12 weeks using either ergocalciferol (D2) or cholecalciferol (D3) 1, 2, 4
• Cholecalciferol (D3) is strongly preferred over ergocalciferol (D2) because it maintains serum levels longer and has superior bioavailability 1, 2
• For severe deficiency (<10 ng/mL), use the full 12-week course rather than 8 weeks 1, 3

Maintenance Phase

• After completing the loading dose, transition to 1,500-2,000 IU daily 1, 2
• An alternative maintenance regimen is 50,000 IU monthly, which is equivalent to approximately 1,600 IU daily 1, 2
• For elderly patients (≥65 years), a minimum of 800 IU daily is recommended, though higher doses of 700-1,000 IU daily reduce fall and fracture risk more effectively 1, 2

Target Levels and Monitoring

• The minimum target level is 25(OH)D ≥30 ng/mL for optimal bone health and anti-fracture efficacy 1, 2
• Anti-fall efficacy begins at ≥24 ng/mL 1
• Recheck 25(OH)D levels after 3-6 months of treatment to confirm adequate response 1, 2
• If using intermittent dosing (weekly or monthly), measure levels just prior to the next scheduled dose 1
• The upper safety limit is 100 ng/mL 1, 2

Essential Co-Interventions

• Ensure adequate calcium intake of 1,000-1,500 mg daily from diet plus supplements if needed 1, 2
• Calcium supplements should be taken in divided doses of no more than 600 mg at once for optimal absorption 1, 2
• Weight-bearing exercise at least 30 minutes, 3 days per week, supports bone health 1

Special Populations

Elderly Patients

• Treat with a minimum of 800 IU daily even without baseline measurement 1, 2
• Higher doses (700-1,000 IU daily) are more effective for reducing fall and fracture risk 1, 2

Chronic Kidney Disease

• For CKD patients with GFR 20-60 mL/min/1.73m², use standard nutritional vitamin D replacement with ergocalciferol or cholecalciferol 1, 2
• CKD patients are at particularly high risk due to reduced sun exposure, dietary restrictions, and increased urinary losses 1

Malabsorption Syndromes

• For patients with documented malabsorption (post-bariatric surgery, inflammatory bowel disease, short-bowel syndrome), intramuscular vitamin D 50,000 IU is preferred when available 1
• IM administration results in significantly higher 25(OH)D levels and lower rates of persistent deficiency compared to oral supplementation 1
• When IM is unavailable or contraindicated, use substantially higher oral doses (4,000-5,000 IU daily) 1
• Post-bariatric surgery patients specifically need at least 2,000 IU daily to prevent recurrent deficiency 1

Dark-Skinned or Veiled Individuals

• Supplement with 800 IU daily without baseline testing due to limited sun exposure 1, 2

Critical Pitfalls to Avoid

• Never use active vitamin D analogs (calcitriol, alfacalcidol, doxercalciferol, paricalcitol) to treat nutritional vitamin D deficiency, as they do not correct 25(OH)D levels 1, 2, 3
• Avoid single very large doses (>300,000 IU) as they may be inefficient or potentially harmful, particularly for fall and fracture prevention 1, 2
• Do not supplement patients with normal vitamin D levels, as benefits are only seen in those with documented deficiency 1, 2
• Correct vitamin D deficiency before initiating bisphosphonates to prevent hypocalcemia 2

Safety Considerations

• Daily doses up to 4,000 IU are generally safe for adults 1, 2, 3
• Some evidence supports up to 10,000 IU daily for several months without adverse effects 1, 3
• Toxicity is rare, typically occurring only with prolonged high doses (>10,000 IU daily) and manifests as hypercalcemia, hypercalciuria, and potential renal issues 1, 2
• Monitor serum calcium, phosphorus, and creatinine to detect hypercalcemia, especially with high-dose regimens 3

Expected Response

• Using the rule of thumb, an intake of 1,000 IU vitamin D daily increases serum 25(OH)D by approximately 10 ng/mL, though individual responses vary due to genetic differences in vitamin D metabolism 1
• The increase in 25(OH)D is related to the dose per kilogram body weight, described by the equation: Δ25(OH)D = 0.025 × (dose per kg body weight) 5