CONCURRENT ADMINISTRATION WITH ALUMINIUM, CALCIUM OR MAGNESIUM SALTS MAY REDUCE ITS ABSORPTION. VITAMINE D INCREASES THE G.I. ABSORPTION OF IT AND INCREASES THE POTENTIAL FOR HYPERPHOSPHATAEMIA. CONCURRENT USED WITH DIURETICS OR OTHER DRUGS THAT MAY BE RISK OF HYPOCALCAEMIA. CONCURRENT USED WITH CALCIUM SUPPLEMTNTS OR CALCIUM-CONTAINING ANTACIDS MAY INCREASE RISK OF ECTOPIC CALCIFICATION.