What is the recommended treatment for vitamin D deficiency?

Treatment for Vitamin D Deficiency

For vitamin D deficiency (<20 ng/mL), prescribe oral ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3) 50,000 IU once weekly for 8-12 weeks, followed by maintenance therapy of 800-2,000 IU daily. 1

Diagnosis and Classification

• Vitamin D deficiency is defined as serum 25-hydroxyvitamin D [25(OH)D] levels below 20 ng/mL (50 nmol/L) 1, 2
• Vitamin D insufficiency is defined as serum 25(OH)D levels between 20-30 ng/mL (50-75 nmol/L) 1, 2
• Severe vitamin D deficiency is defined as levels below 10-12 ng/mL, which significantly increases risk for osteomalacia and nutritional rickets 1

Treatment Protocol Based on Deficiency Severity

Initial Treatment Phase

• For vitamin D deficiency (<20 ng/mL), prescribe a loading dose: ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3) 50,000 IU once weekly for 8-12 weeks 1, 2
• For severe deficiency (<10 ng/mL), especially with symptoms or high fracture risk, 50,000 IU weekly for 12 weeks is recommended 1
• Single very large doses (>300,000 IU) should be avoided as they may be inefficient or potentially harmful 1, 3

Maintenance Phase

• After completing the loading dose regimen, transition to a maintenance dose of 800-2,000 IU daily 1, 2
• For convenience, a monthly dose of 50,000 IU can achieve the equivalent of approximately 1,600 IU daily 1
• Ensure adequate calcium intake alongside vitamin D supplementation, with a recommended daily intake of 1,000-1,500 mg 1

Special Populations

• For patients with malabsorption syndromes or those who have undergone bariatric surgery, higher doses may be required or intramuscular (IM) vitamin D administration should be considered 1
• For elderly patients (≥65 years), higher doses of 700-1,000 IU daily are recommended to reduce fall and fracture risk 1
• For obese patients, patients with liver disease, or those with malabsorption syndromes, higher daily doses of 7,000 IU or intermittent doses of 30,000 IU/week may be necessary 4
• For patients with chronic kidney disease (CKD) and GFR of 20-60 mL/min/1.73m², vitamin D deficiency can be treated with ergocalciferol or cholecalciferol 1

Monitoring Response to Treatment

• Follow-up vitamin D levels should be measured after 3-6 months of treatment to ensure adequate dosing and response 1
• Target serum 25(OH)D level should be at least 30 ng/mL for optimal health benefits, particularly for anti-fracture efficacy 1
• If using an intermittent regimen (weekly, monthly), measurement should be performed just prior to the next scheduled dose 1
• Individual response to vitamin D supplementation is variable due to genetic differences in vitamin D metabolism, making monitoring essential 1

Safety Considerations

• Daily doses up to 4,000 IU are generally considered safe for adults 1, 5
• Symptoms of vitamin D toxicity include hypercalcemia, hyperphosphatemia, suppressed parathyroid hormone, and hypercalciuria 1
• The expert panel agreed on an upper safety limit for 25(OH)D of 100 ng/mL 1
• When high therapeutic doses are used, progress should be followed with frequent blood calcium determinations 6

Common Pitfalls and Caveats

• Failing to account for other sources of vitamin D (fortified foods, dietary supplements, self-administered products) when prescribing therapeutic doses 6
• Not ensuring adequate calcium intake alongside vitamin D supplementation, which is necessary for clinical response to vitamin D therapy 6
• Overlooking potential drug interactions, such as mineral oil interfering with absorption of vitamin D or thiazide diuretics potentially causing hypercalcemia in patients receiving vitamin D therapy 6
• Using single large doses (300,000-500,000 IU) which should be avoided due to potential inefficiency or harm 1, 3
• Failing to recognize that inflammation can significantly reduce plasma vitamin D levels, complicating interpretation when C-reactive protein (CRP) > 40 mg/L 1