Therefore, oral vitamin D is given as calcitriol, initially 5 to 10 ng / kg 2 times a day. This, however, is not the case with HHRH or HHN (hypophosphatemia, hypercalcemia, and nephrocalcinosis), where 1, 25-dihydroxyvitamin D3 levels are elevated and dosing with calcitriol can be detrimental.