Effect of different doses of parenteral vitamin D3 on serum 25 (OH) D concentrations

Background and the purpose of the study:Parenteral Vitamin D3 is commonly prescribed in some developing countries like Iran and data about its effects on serum 25(OH)D concentration are scanty. Current study was designed to evaluate the effects of different doses of parenteral vitamin D3 on serum 25(OH)D concentration. Forty two healthy volunteer were selected and randomly assigned into 3groups. Groups I and II received 300000 and 600000 units of intramuscular vitamin D3and group III received placebo. Serum 25 (OH)D concentration were evaluated before,2 weeks, 2 months and 4 months after injection.Results and major Serum 25(OH)D in groups I and II were significantly higher than those before injection (<0.001). At the end of the study, serum 25(OH)D concentration in groups I,II, and III were 48.20 ± 28.32 ng/ml, 65.46 ± 33.52 ng/ml, and 14.38±11.14 ng/ml, respectively. Relative frequency of serum 25 (OH) D above 80 ng/l in groups I, II and was %20 and %33.3 respectively. One case in group I and one case in group II (in two sessions) showed 25(OH)D concentration above 100 ng/ml. Vitamin D injection especially at doses higher than 300000 IU may be associated with 25(OH)D concentration higher than the accepted normal values.