Osteoporosis treatment by a new active vitamin D3 compound, eldecalcitol, in Japan.

Although vitamin D is used mainly as a nutritional supplement in osteoporosis treatment, its active form, 1,25-dihydroxyvitamin D [1,25(OH)(2)D], has an effect to maintain bone remodeling balance as well. Eldecalcitol is an analog of 1,25(OH) (2)D(3) with stronger effects than its native form in improving bone remodeling balance and increasing bone mineral density in osteoporotic patients. Daily 0.75 μg eldecalcitol is superior to 1.0 μg alfacalcidol in preventing new vertebral fractures under vitamin D supplementation, and is approved for osteoporosis treatment in Japan. Eldecalcitol also decreases wrist fractures. Further studies are warranted to examine the effect of eldecalcitol on other nonvertebral fractures, extraskeletal systems including falls, and combined treatment with other drugs in osteoporotic patients, as well as the mechanism of action of eldecalcitol.