Intermittent high-dose vitamin D prophylaxis during infancy: effect on vitamin D metabolites, calcium, and phosphorus.
In infants receiving intermittent high dose vitamin D prophylaxis (600,000 IU ergocalciferol per dose orally) every 3-5 mo, the serum concentrations of vitamin D metabolites, calcium (Ca), and phosphorus (P) were determined before and 2 wk after each dose. The 25-hydroxyvitamin D (OHD) concentrations increased to well above normal but the values returned to the normal range before each subsequent dose. The 24,25- and 25,26-dihydroxyvitamin D ([OH]2D) levels followed a pattern similar to that of 25-OHD, and both were closely related to the latter (r = 0.85, p less than 0.005, and r = 0.84, p less than 0.005, respectively). The 1,25-(OH)2D concentrations did not vary in a consistent pattern and remained largely within the normal range. All infants had normal Ca levels before the first dose but 14 infants (34%) later had one or both Ca values above the upper normal limit of 2.80 mmol/L (2.81-3.32 mmol/L), indicating that the vitamin D doses were excessive despite the lack of accumulative increases in serum vitamin D concentrations.
D015650:24,25-Dihydroxyvitamin D 3; D015652:25-Hydroxyvitamin D 2; D000367:Age Factors; D002112:Calcifediol / Q000097:blood; D002118:Calcium / Q000097:blood*; D004100:Dihydroxycholecalciferols / Q000097:blood; D004305:Dose-Response Relationship, Drug; D004872:Ergocalciferols / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010758:Phosphorus / Q000097:blood*; D012279:Rickets / Q000517:prevention & control; D014807:Vitamin D / Q000097:blood*
D004100:Dihydroxycholecalciferols; D004872:Ergocalciferols; D014807:Vitamin D; D015652:25-Hydroxyvitamin D 2; D010758:Phosphorus; D015650:24,25-Dihydroxyvitamin D 3; D002112:Calcifediol; D002118:Calcium