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Effect of a Single Oral Dose of 600,000 IU of Cholecalciferol on Serum Calciotropic Hormones in Young Subjects with Vitamin D Deficiency: A Prospective Intervention Study.

J Clin Endocrinol Metab. 2010 Jul 21.
Cipriani C, Romagnoli E, Scillitani A, Chiodini I, Clerico R, Carnevale V, Mascia ML, Battista C, Viti R, Pileri M, Eller-Vainicher C, Minisola S.

Departments of Clinical Sciences (C.C., E.R., M.L.M., S.M.) and Dermatology (R.C.), University of Rome "Sapienza," 00161 Rome, Italy; Units of Endocrinology (A.S., C.B., R.V.), Internal Medicine (V.C.), and Clinical Chemistry (M.P.), Instituto di Ricovero e Cura a Carattere Scientifico (IRCCS) "Casa Sollievo della Sofferenza" Hospital, 71013 San Giovanni Rotondo, Italy; and Department of Medical Sciences (I.C., C.E.-V.), University of Milan, Fondazione Policlinico IRCCS, 20122 Milan, Italy.

Context: Effects of vitamin D repletion in young people with low vitamin D status have not been investigated so far. Objective: We evaluated the effect of a single massive dose of cholecalciferol on calcium metabolism at 3, 15, and 30 d, compared to baseline.

Design and Setting: We conducted a prospective intervention study in an ambulatory care setting.

Participants: Forty-eight young subjects with vitamin D deficiency participated in the study.

Intervention: A single oral dose of 600,000 IU of cholecalciferol was administered to each subject.

Main Outcome Measures: We evaluated serum changes of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D, calcium, and PTH induced by a single load of cholecalciferol.

Results: The 25(OH)D level was
15.8 +/- 6.5 ng/ml at baseline and became
77.2 +/- 30.5 ng/ml at 3 d (P < 0.001) and
62.4 +/- 26.1 ng/ml at 30 d (P < 0.001).
PTH levels concomitantly decreased from 53.0 +/- 20.1 to 38.6 +/- 17.2 pg/ml at 3 d and to 43.4 +/- 14.0 pg/ml at 30 d (P < 0.001 for both). The trends were maintained in a subgroup followed up to 90 d (P < 0.001). Mean serum Ca and P significantly increased compared to baseline, whereas serum Mg decreased at 3 d. 1,25-Dihydroxyvitamin D significantly increased from 46.8 +/- 18.9 to 97.8 +/- 38.3 pg/ml at 3 d (P < 0.001) and to 59.5 +/- 27.3 pg/ml at 60 d (P < 0.05).

Conclusions: A single oral dose of 600,000 IU of cholecalciferol rapidly enhances 25(OH)D and reduces PTH in young people with vitamin D deficiency.
PMID: 20660032

The accelerated vitamin D3 dosing schedule of 20,000 IU/day with a 50,000 IU loading dose once a week still works fine.

If you work with a physician and schedule lab tests for 25(OH)D, total calcium and PTC you can increase the vitamin D3 loading dose to 100,000 IU or 150,000 IU once a week.

Take care,

V/R, Batch