Calcitriol

Calcitriol injection is indicated in the management of hypocalcemia in patients undergoing chronic renal dialysis. It has been shown to significantly reduce elevated parathyroid hormone levels. Reduction of PTH has been shown to result in an improvement in renal osteodystrophy.

Calcitriol injection should not be given to patients with hypercalcemia or evidence of vitamin D toxicity. Calcitriol injection is contraindicated in patients with previous hypersensitivity to calcitriol or any of its excipients.

Since calcitriol is the most potent metabolite of vitamin D available, prescription-based doses of vitamin D and its derivatives should be withheld or used with caution during treatment to avoid the risk of hypercalcemia. A non-aluminum phosphate-binding compound should be used to control serum phosphorous levels in patients undergoing dialysis. Overdosage of any form of vitamin D is dangerous (see also OVERDOSAGE ).

Progressive hypercalcemia due to overdosage of vitamin D and its metabolites may be so severe as to require emergency attention. Chronic hypercalcemia can lead to generalized vascular calcification, nephrocalcinosis and other soft tissue calcification. The serum calcium times phosphate (Ca x P) product should not be allowed to exceed 70 mg 2 /dL 2 . Radiographic evaluation of suspect anatomical regions may be useful in the early detection of this condition.

Drug Interactions Concomitant use of magnesium-containing preparations should be used with caution or avoided since such use may lead to the development of hypermagnesemia. Corticosteroids with glucocorticoid activity may counteract the bone and mineral metabolism effects of vitamin D analogues. Cytochrome P450 enzyme-inducing anticonvulsants such as carbamazepine, phenobarbital and phenytoin may reduce the effects of vitamin D because they increase vitamin D catabolism.