Calcitriol
Dosing in kidney impairment
When the optimal dosage of calcitriol has been determined, serum calcium levels should be checked every month (or as given below for individual indications). Samples for serum calcium estimation should be taken without a tourniquet. Dialysis Patients The recommended initial dose of calcitriol is 0.25 mcg/day. If a satisfactory response in the biochemical parameters and clinical manifestations of the disease state is not observed, dosage may be increased by 0.25 mcg/day at 4- to 8-week intervals.
Most patients undergoing hemodialysis respond to doses between 0.5 and 1 mcg/day. Oral calcitriol may normalize plasma-ionized calcium in some uremic patients, yet fail to suppress parathyroid hyperfunction. In these individuals with autonomous parathyroid hyper-function, oral calcitriol may be useful to maintain normocalcemia, but has not been shown to be adequate treatment for hyperparathyroidism.
The number of treated patients with pseudohypoparathyroidism less than 6 years of age is too small to make dosage recommendations. Malabsorption is occasionally noted in patients with hypoparathyroidism; hence, larger doses of calcitriol may be needed. Predialysis Patients The recommended initial dosage of calcitriol is 0.25 mcg/day in adults and pediatric patients 3 years of age and older.
Preparation and administration
DOSAGE & ADMINISTRATION The optimal daily dose of calcitriol oral solution must be carefully determined for each patient. Calcitriol is administered orally as an oral solution (1 mcg/mL). Calcitriol therapy should always be started at the lowest possible dose and should not be increased without careful monitoring of serum calcium.