How do I write a vitamin D order?

How to Write a Vitamin D Order

For standard vitamin D supplementation, order cholecalciferol (vitamin D3) 3,000 IU daily, titrated to reach target 25(OH)D levels ≥30 ng/mL (75 nmol/L). 1, 2

Vitamin D Order Writing Guidelines

Standard Dosing Format

• Specify the form: Cholecalciferol (vitamin D3) preferred over ergocalciferol (vitamin D2)
• Specify the dose: In international units (IU)
• Specify frequency: Daily, weekly, or monthly regimen
• Specify route: Oral (PO)
• Specify duration: Ongoing or for specific period
• Include target 25(OH)D level: ≥30 ng/mL (75 nmol/L)

Population-Specific Dosing

General Adult Population:

• Ages 19-70 years: 600-800 IU daily
• Ages >70 years: 800 IU daily 2

Special Populations:

• Bariatric surgery patients: 3,000 IU daily, titrated up to 6,000 IU daily as needed 1
• Severe malabsorption: 50,000 IU 1-3 times weekly to daily 1
• Obesity: 2-3 times higher doses (up to 7,000 IU daily) 2, 3
• Chronic kidney disease: Specialized approaches based on GFR and PTH levels 1, 2

Treatment of Deficiency Based on Vitamin D Levels

• Mild deficiency (15-20 ng/mL): 800-1,000 IU daily 2
• Moderate deficiency (5-15 ng/mL): 50,000 IU weekly for 8 weeks, then maintenance 2, 4
• Severe deficiency (<5 ng/mL): 50,000 IU weekly for 8-12 weeks, then maintenance 2, 5

Sample Orders

1. Standard maintenance order:

   • "Cholecalciferol (vitamin D3) 800 IU PO daily"

2. Bariatric surgery patient:

   • "Cholecalciferol (vitamin D3) 3,000 IU PO daily, titrate to target 25(OH)D level ≥30 ng/mL" 1

3. Vitamin D deficiency treatment:

   • "Cholecalciferol (vitamin D3) 50,000 IU PO weekly for 8 weeks, then 800 IU PO daily maintenance" 4

4. Severe malabsorption:

   • "Cholecalciferol (vitamin D3) 50,000 IU PO weekly; check 25(OH)D level in 3 months" 1

Monitoring Parameters

• Check 25(OH)D levels 3-4 months after initiating therapy
• For maintenance therapy, monitor annually
• After dose adjustments, recheck in 3-6 months 1, 2
• Monitor serum calcium and phosphorus with high-dose supplementation

Important Considerations

• Upper safety limit for vitamin D is generally 4,000 IU daily for adults 2
• Vitamin D toxicity is rare but can occur with prolonged high doses (>10,000 IU daily) 2
• Ensure adequate calcium intake (1,000-1,500 mg daily) alongside vitamin D supplementation 2
• For patients with CKD, do not initiate active vitamin D therapy if serum calcium >9.5 mg/dL or phosphorus >4.6 mg/dL 1

Common Pitfalls to Avoid

• Underdosing in high-risk populations (obesity, malabsorption)
• Failure to specify vitamin D form (D2 vs. D3)
• Inadequate monitoring of 25(OH)D levels after initiating therapy
• Not considering drug interactions that affect vitamin D metabolism
• Single large doses (300,000-500,000 IU) should be avoided 6