Calcitriol Other names: 1,25-dihydroxycholecalciferol 1,25-dihydroxyvitamin D3

Magnesium-containing drugs (e.g. antacids) may cause hypermagnesemia and should therefore not be taken during therapy with calcitriol by patients on chronic renal dialysis.

Concomitant treatment with a thiazide diuretic increases the risk of hypercalcaemia.

Bile acid sequestrants including cholestyramine and sevelamer can reduce intestinal absorption of fat-soluble vitamins and therefore may impair intestinal absorption of calcitriol.

A relationship of functional antagonism exists between vitamin D analogues, which promote calcium absorption, and corticosteroids, which inhibit it.

Calcitriol dosage must be determined with care in patients undergoing treatment with digitalis, as hypercalcaemia in such patients may precipitate cardiac arrhythmias.

The safety of calcitriol during pregnancy has not been established.

Supravalvular aortic stenosis has been produced in foetuses by near-fatal oral doses of vitamin D in pregnant rabbits. There is no evidence to suggest that vitamin D is teratogenic in humans even at very high doses. Calcitriol should be used during pregnancy only if the benefits outweigh the potential risk to the foetus.

It should be assumed that exogenous calcitriol passes into breast milk. Calcitriol has been found in milk of lactating dams. Due to the lack of human data, it should not be used during breastfeeding.

In view of the potential for hypercalcaemia in the mother and for adverse reactions from calcitriol in nursing infants, mothers may breastfeed while taking calcitriol, provided that the serum calcium levels of the mother and infant are monitored.

On the basis of the pharmacodynamic profile of reported adverse events, this product is presumed to be safe or unlikely to adversely affect such activities.