What is the recommended oral treatment for vitamin D deficiency?

Oral Treatment of Vitamin D Deficiency

The recommended oral treatment for vitamin D deficiency is cholecalciferol (vitamin D3) at a dose of 50,000 IU weekly for 4-8 weeks for patients with levels between 5-15 ng/mL, followed by maintenance therapy of 800-1,000 IU daily. 1

Dosing Strategies Based on Deficiency Severity

Treatment should be tailored according to the severity of vitamin D deficiency:

• Mild deficiency (15-20 ng/mL): 800-1,000 IU daily 1
• Moderate deficiency (5-15 ng/mL): 50,000 IU weekly for 4-8 weeks, then maintenance therapy 1
• Severe deficiency (<5 ng/mL): Individualized treatment under close monitoring 1

For repletion therapy, cholecalciferol (vitamin D3) is preferred over ergocalciferol (vitamin D2) due to its higher bioefficacy 1.

Special Population Considerations

Different populations may require adjusted dosing:

• Patients with obesity: 2-3 times higher doses (up to 7,000 IU daily) due to sequestration in adipose tissue 1
• Bariatric surgery patients: At least 2,000 IU daily, up to 3,000-6,000 IU daily as needed 2, 1
• Severe malabsorption: 50,000 IU 1-3 times weekly to daily 1
• Patients with liver disease: Higher doses due to impaired hepatic 25-hydroxylation 1

Administration Route

• Oral administration is the standard route for most patients
• Intramuscular administration should be considered for patients with malabsorptive conditions, particularly after malabsorptive bariatric surgery 2
  • IM administration results in higher 25(OH)D levels and lower rates of vitamin D insufficiency compared to oral administration in patients with malabsorption 2

Formulation and Dosage Forms

Cholecalciferol is available in various formulations:

• Daily doses (800-1,000 IU)
• Weekly high-dose formulations (50,000 IU) 3

The FDA-approved high-dose vitamin D3 product label indicates taking one 50,000 IU capsule weekly or as directed by a physician, taken with food 3.

Monitoring

• Check 25(OH)D levels at least 3 months after starting supplementation
• Monitor yearly once target level is achieved
• For patients with CKD, check calcium and phosphorus at 1 month after initiation or dose change, then every 3 months during repletion phase 1

Safety Considerations

• Vitamin D toxicity is rare and typically occurs with much higher doses (>10,000 IU daily for extended periods)
• Serum 25-hydroxyvitamin D levels >150 ng/mL indicate toxicity 1
• Ensure adequate calcium intake (1000-1500 mg daily) alongside vitamin D supplementation for optimal bone health 1
• Patients taking thiazide diuretics may be at greater risk of toxicity 3

Common Pitfalls to Avoid

• Underdosing: Insufficient dosing fails to correct deficiency and improve clinical outcomes
• Using incorrect formulation: Cholecalciferol (D3) is preferred over ergocalciferol (D2) for most patients 1
• Inadequate duration of therapy: Short-term supplementation without maintenance therapy leads to recurrence of deficiency
• Failure to address underlying causes: Not identifying and addressing causes of deficiency (malabsorption, inadequate intake, etc.)
• Neglecting calcium supplementation: Vitamin D supplementation should be accompanied by adequate calcium intake for optimal bone health 1

The goal of treatment should be to achieve and maintain serum 25(OH)D levels above 30 ng/mL, which has been associated with reduced risk of fractures and falls in older adults 1.