Vitamin D3 60,000 IU Treatment Protocol
For vitamin D deficiency, administer 60,000 IU of vitamin D3 weekly for 8-12 weeks as the loading phase, followed by maintenance therapy of 2,000 IU daily or 50,000 IU monthly to sustain optimal levels above 30 ng/mL. 1
Loading Phase Duration and Dosing
The standard loading regimen is 50,000-60,000 IU weekly for 8-12 weeks, with 12 weeks recommended for severe deficiency (levels <10 ng/mL) and 8 weeks for moderate deficiency (10-20 ng/mL). 1, 2
Each weekly dose should be taken with the largest, fattiest meal of the day to maximize absorption, as vitamin D is fat-soluble and requires dietary fat for optimal intestinal uptake. 1
This cumulative dose of 480,000-720,000 IU over the treatment period typically raises 25(OH)D levels by 40-70 ng/mL, which should bring most patients to target levels of at least 30 ng/mL. 1
Maintenance Phase After Loading
After completing the 8-12 week loading phase, transition to maintenance therapy with 2,000 IU daily or 50,000 IU monthly (equivalent to approximately 1,600 IU daily). 1, 2
Vitamin D3 (cholecalciferol) is strongly preferred over D2 (ergocalciferol) for maintenance therapy because it maintains serum levels longer and has superior bioavailability, particularly with intermittent dosing schedules. 1, 2
For elderly patients (≥65 years), a minimum maintenance dose of 800 IU daily is recommended, though higher doses of 700-1,000 IU daily more effectively reduce fall and fracture risk. 1
Monitoring Protocol
Measure 25(OH)D levels 3 months after initiating treatment to allow sufficient time for vitamin D levels to plateau and accurately reflect response to supplementation, given vitamin D's long half-life. 1, 2
If using intermittent dosing (weekly or monthly), measure levels just prior to the next scheduled dose for accurate assessment. 1
The target 25(OH)D level should be at least 30 ng/mL for optimal health benefits, particularly for anti-fracture efficacy, while anti-fall efficacy begins at 24 ng/mL. 1, 2
Once stable and in target range, recheck 25(OH)D levels at least annually. 1
Essential Co-Interventions
Ensure adequate calcium intake of 1,000-1,500 mg daily from diet plus supplements if needed, as adequate calcium is necessary for clinical response to vitamin D therapy. 1, 2
Calcium supplements should be taken in divided doses of no more than 600 mg at once for optimal absorption, separated by at least 2 hours from the vitamin D dose. 1
Recommend weight-bearing exercise for at least 30 minutes, 3 days per week, along with smoking cessation and alcohol limitation to support bone health. 1
Special Population Considerations
Chronic Kidney Disease (CKD Stages 3-4)
For CKD patients with GFR 20-60 mL/min/1.73m², use standard nutritional vitamin D replacement with cholecalciferol or ergocalciferol—the same loading duration (8-12 weeks) applies. 3, 1
Never use active vitamin D analogs (calcitriol, alfacalcidol, doxercalciferol, paricalcitol) to treat nutritional vitamin D deficiency, as they bypass normal regulatory mechanisms, do not correct 25(OH)D levels, and carry higher risk of hypercalcemia. 3, 1
CKD patients are at particularly high risk due to reduced sun exposure, dietary restrictions, urinary losses of 25(OH)D, and reduced endogenous synthesis. 3, 1
Malabsorption Syndromes
For patients with documented malabsorption (post-bariatric surgery, inflammatory bowel disease, celiac disease, short bowel syndrome), intramuscular vitamin D3 50,000 IU is the preferred route when available, as it 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: 50,000 IU 2-3 times weekly for 8-12 weeks, followed by at least 2,000 IU daily for maintenance. 1, 4
Obesity
Obese patients may require higher maintenance doses (2,000-4,000 IU daily) due to vitamin D sequestration in adipose tissue. 2, 4
Without monitoring of 25(OH)D, daily doses of 7,000 IU or intermittent doses of 30,000 IU weekly should be considered for prolonged maintenance in obese patients. 4
Safety Considerations
Daily doses up to 4,000 IU are generally safe for adults, with some evidence supporting up to 10,000 IU daily for several months without adverse effects. 3, 1, 2
The 60,000 IU weekly regimen (equivalent to approximately 8,500 IU daily) has been safely tolerated in clinical studies for up to 12 months without causing hypercalcemia or changes in renal function. 5
Avoid single ultra-high loading doses (>300,000-540,000 IU) as they may be inefficient or potentially harmful, particularly for fall and fracture prevention. 1, 2
The upper safety limit for 25(OH)D is 100 ng/mL—toxicity typically only occurs with prolonged daily doses exceeding 10,000 IU or serum levels above 100 ng/mL. 1, 2
Monitor serum calcium and phosphorus at least every 3 months during the loading phase, and discontinue all vitamin D therapy immediately if serum corrected total calcium exceeds 10.2 mg/dL (2.54 mmol/L). 1
Critical Pitfalls to Avoid
Do not use this regimen for vitamin D insufficiency (20-30 ng/mL)—for insufficiency, adding 1,000 IU daily and rechecking in 3 months is more appropriate. 1
Do not measure vitamin D levels too early (before 3 months), as this will not reflect true steady-state levels and may lead to inappropriate dose adjustments. 1
Verify patient adherence with the prescribed regimen before increasing doses for inadequate response, as poor compliance is a common reason for treatment failure. 1
Ensure total 25-hydroxyvitamin D (D3 and D2) is measured if the patient is on vitamin D2 supplements (ergocalciferol). 1
Expected Clinical 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 significantly due to genetic differences in vitamin D metabolism. 1, 2, 6
The 60,000 IU weekly regimen typically raises levels from deficient ranges to at least 30-50 ng/mL after 8-12 weeks in most patients with normal absorption. 1, 5