Comparison of the short-term effects of three oral calcium-vitamin D formulations and placebo on calcium metabolism

Abstract

The aim of the present trial was to evaluate and compare the short-term effects of oral administration of three fixed calcium (CA) and vitamin D 3 formulations with those of placebo on CA metabolism. The study population comprised 18 healthy male volunteers (mean age, 23.9 ± 0.9 years). After a 21-day washout period, subjects were randomly allocated to receive one of three formulations of elemental CA 1000 mg and vitamin D 3 800 IU (Orocal ® Vitamin D 3, Ideos ®, Cacit® Vitamin D 3) or placebo. These drugs were given once daily (after an overnight fast) for 8 days. Serum concentrations of CA, parathyroid hormone (PTH), 25-hydroxyvitamin D 3 (25[OH]D 3), and 1,25-dihydroxyvitamin D 3 (1,25[OH] 2D 3) were measured before drug administration on days 1 and 8; serum concentrations of CA and PTH were measured every 30 minutes from 60 to 180 minutes after drug administration on day 1 and 120 minutes after administration on day 8. On days 1 and 8, each of the CA-vitamin D 3 formulations induced a significant increase in serum CA concentration compared with baseline values. On day 1, only Orocal and Cacit induced an increase in serum CA concentration that was significantly different from placebo. On days 1 and 8, each of the three formulations induced a significant decrease in serum PTH concentration compared with baseline values and placebo; however, differences were not statistically significant in PTH suppression between the three drugs. After 8 days of treatment, no significant changes in serum 1,25(OH) 2D 3 concentration were observed compared with baseline values for any of the medications. Orocal induced a significant variation in serum 25(OH)D 3 compared with baseline values and with placebo. In conclusion, the three study drugs significantly increased serum CA and decreased serum PTH concentrations compared with baseline values and significantly suppressed PTH secretion compared with placebo. The increase in serum CA concentration compared with placebo was significantly different. Only Orocal demonstrated a significant increase in serum 25(OH)D 3 after 8 days of treatment.