What is the recommended treatment for vitamin D deficiency?

Treatment of Vitamin D Deficiency

For documented vitamin D deficiency (<20 ng/mL), treat with ergocalciferol 50,000 IU once weekly for 8-12 weeks, followed by maintenance therapy with cholecalciferol 800-2,000 IU daily, targeting a serum 25(OH)D level of at least 30 ng/mL. 1, 2

Defining Deficiency and Treatment Goals

• Vitamin D deficiency is defined as serum 25(OH)D below 20 ng/mL, while insufficiency ranges from 20-30 ng/mL 1, 2, 3
• Severe deficiency (below 10-12 ng/mL) significantly increases risk for osteomalacia, rickets, and excess mortality 1, 2
• The treatment target is at least 30 ng/mL for anti-fracture efficacy, while anti-fall benefits begin at 24 ng/mL 1, 2
• The upper safety limit is 100 ng/mL to avoid toxicity 1, 2

Standard Treatment Protocol

Loading Phase (Weeks 1-8 or 1-12)

• For standard deficiency (10-20 ng/mL): ergocalciferol 50,000 IU once weekly for 8 weeks 1, 2, 3
• For severe deficiency (<10 ng/mL): ergocalciferol 50,000 IU once weekly for 12 weeks 1, 2
• An alternative for severe deficiency with symptoms or high fracture risk is 8,000 IU daily for 4 weeks, then 4,000 IU daily for 2 months 1

Maintenance Phase (After Loading)

• Transition to cholecalciferol (vitamin D3) 800-2,000 IU daily 1, 2, 3
• Cholecalciferol is strongly preferred over ergocalciferol for maintenance because it maintains serum levels longer and has superior bioavailability, especially with intermittent dosing 1, 2
• An alternative maintenance regimen is 50,000 IU monthly (equivalent to approximately 1,600 IU daily) 1

Essential Co-Interventions

• Ensure adequate calcium intake of 1,000-1,500 mg daily from diet plus supplements if needed, as adequate dietary calcium is necessary for response to vitamin D therapy 1, 2, 4
• Calcium supplements should be taken in divided doses of no more than 600 mg at once for optimal absorption 1
• Encourage weight-bearing exercise at least 30 minutes, 3 days per week 1, 2

Special Populations Requiring Modified Approaches

Malabsorption Syndromes

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

Chronic Kidney Disease

• For CKD stages 3-4 (GFR 20-60 mL/min/1.73m²): use standard nutritional vitamin D replacement with ergocalciferol or cholecalciferol 1, 2
• Never use active vitamin D analogs (calcitriol, alfacalcidol, doxercalciferol, paricalcitol) to treat nutritional vitamin D deficiency, as they bypass normal regulatory mechanisms and do not correct 25(OH)D levels 1, 2
• CKD patients are at particularly high risk due to reduced sun exposure, dietary restrictions, and urinary losses 1

Elderly Patients

• For patients ≥65 years: minimum 800 IU daily is recommended, though 700-1,000 IU daily more effectively reduces fall and fracture risk 1, 2
• Dark-skinned or veiled individuals with limited sun exposure should receive 800 IU daily without requiring baseline measurement 1

Monitoring Protocol

• Recheck 25(OH)D levels 3 months after initiating treatment to allow serum levels to reach plateau and accurately reflect treatment response 1, 2
• If using intermittent dosing (weekly or monthly), measure levels just prior to the next scheduled dose 1, 2
• Individual response to supplementation is highly variable due to genetic differences in vitamin D metabolism, making monitoring essential 1, 2
• Continue monitoring serum calcium every 3 months during treatment 1
• Once stable, recheck 25(OH)D levels annually 1

Safety Considerations

• Daily doses up to 4,000 IU are generally safe for adults 1, 2, 5
• Vitamin D toxicity is rare but can occur with prolonged daily doses exceeding 10,000 IU or serum 25(OH)D levels above 100 ng/mL 1, 2
• Avoid single very large doses (>300,000 IU) as they may be inefficient or potentially harmful 1, 5
• Toxicity symptoms include hypercalcemia, hyperphosphatemia, suppressed parathyroid hormone, and hypercalciuria 1, 2

Expected Response to Treatment

• Using the rule of thumb: 1,000 IU daily increases serum 25(OH)D by approximately 10 ng/mL, though individual responses vary 1, 2
• The standard 50,000 IU weekly regimen for 8-12 weeks typically raises 25(OH)D levels by approximately 16-28 ng/mL 1

Critical Pitfalls to Avoid

• Do not screen asymptomatic adults for vitamin D deficiency, as the USPSTF concludes that evidence on screening to improve health outcomes is insufficient and the balance of benefits and harms cannot be determined 6
• Do not use active vitamin D analogs for nutritional deficiency 1, 2
• Do not ignore compliance, as poor adherence is a common reason for inadequate response 1
• Do not measure vitamin D levels too early (before 3 months), as this will not reflect steady-state levels and may lead to inappropriate dose adjustments 1
• For patients with persistent severe deficiency despite standard treatment, investigate for malabsorption syndromes 1