COMPARISON OF THE SHORT-TERM EFFECTS OF 3 ORAL CALCIUM-VITAMIN-D FORMULATIONS AND PLACEBO ON CALCIUM-METABOLISM

The aim of the present trial Ras to evaluate and compare the short-ter m effects of oral administration of three fired calcium (CA) and vitam in 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 alloca ted to receive one of three formulations of elemental CA 1000 mg and v itamin D3 800 IU (Orocal(R) Vitamin D-3, Ideos(R), Cacit(R) Vitamin D- 3) or placebo. These drugs were given once daily (after an overnight f ast) for 8 days. Serum concentrations of CA, parathyroid hormone (PTH) , 25-hydroxyvitamin D-3 (25[OH]D-3), and 1,25-dihydroxyvitamin D-8 (1, 25[OH](2)D-3) were measured before drug administration on days I and 8 ; serum concentrations of CA and PTH were measured every 30 minutes fr om 60 to 180 minutes after drug administration on day 1 and 120 minute s after administration on day 8. On days 1 and 8, each of the CA-vitam in D-3 formulations induced a significant increase in serum CA concent ration compared with baseline values. On day 1, only Orocal and Cacit induced an increase in serum CA concentration that was significantly d ifferent from placebo. On days 1 and 8, each of the three formulations induced a significant decrease in serum PTH concentration compared wi th baseline values and placebo; however, differences were not statisti cally significant in PTH suppression between the three drugs. After 8 days of treatment, no significant changes in serum 1,25(OH)(2)D-3 conc entration were observed compared with baseline values for any of the m edications. Orocal induced a significant variation in serum 25(OH)D-3 compared with baseline values and with placebo. In conclusion, the thr ee study drugs significantly increased serum CA and decreased serum PT H concentrations compared with baseline values and significantly suppr essed PTH secretion compared with placebo. The increase in serum CA co ncentration compared with placebo was significantly different. Only Or ocal demonstrated a significant increase in serum 25(OH)D-3 after 8 da ys of treatment.