The Pharmacokinetics of a Single Large Dose of Vitamin D3

Study Overview
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Brief Summary
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When people eat a meal, some, but not all of the calcium in that meal is absorbed, that is, moved into the bloodstream. When the skin is exposed to sunlight during summer months, Vitamin D is made there and then modified into more active forms by the liver and kidneys. These more active forms of Vitamin D improve calcium absorption. Many adults living in the U.S. have little or no sun exposure and are low in Vitamin D. A single dose of 100,000 IU of Vitamin D3 has been used both as empiric treatment for Vitamin D deficiency as well as in controlled trials without risk of raising blood calcium to dangerous levels.This study is to determine the serum levels of Vitamin D and 25-hydroxyvitamin D (vitamin D after it has been modified by the liver) that can be expected when Vitamin D3 is given as a single oral dose of 100,000 IU.

Detailed Description
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The group receiving the supplement will be scheduled for short visits to our research center at baseline and days 1,3,5,7 and then weekly for 3 weeks and then every other week for 6 visits (total 14 visits in 4 months). The group not receiving supplement will be scheduled for short visits at baseline and in 4 months. At the beginning of the study we will measure your height, weight, skin color, and draw blood to measure your blood levels of Vitamin D, 25-hydroxyvitamin D, calcium and parathyroid hormone. At each visit we will draw blood to measure your blood levels of Vitamin D and 25-hydroxyvitamin D. There will be fourteen blood draws for a total of 280 cc of blood drawn (about 4 teaspoons drawn each time) in the supplemented group. There will be 2 blood draws in the group not receiving supplements for a total of 60 cc of blood drawn (about 4 teaspoons drawn each time).

Official Title
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The Pharmacokinetics of a Single Large Dose of Vitamin D3

Conditions
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Vitamin D Deficiency

Intervention / Treatment
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* Drug: cholecalciferol.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy with limited sun exposure of less than 10 hours per week and daily milk consumption of less than 0.47 L (16 oz.). Exclusion Criteria: those with granulomatous conditions, liver disease, kidney disease, or diabetes and those taking anticonvulsants, barbiturates, or steroids in any form.

Ages Eligible for Study
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Minimum Age: 19 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: cholecalciferol<br>A single dose of 100,000 IU vitamin D | Drug: cholecalciferol.<br>* 100,000 IU of Vitamin D<br>* Other names: vitamin D;|
| No Intervention: Control<br>No drug was given | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| to assess the time course and response of serum 25-OHD with a single oral dose of 100,000 IU cholecalciferol. |  | 4 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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vitamin D, cholecalciferol, 25-hydroxyvitamin D