The use of phosphate binders in renal failure should be in conjunction with dietary advice regarding phosphate intake and methods of dialysis appropriate to the patient.
The dose will need to be adjusted depending on phosphate intake or removal by dialysis and on the ensuing effect on serum calcium. This requires regular monitoring, for example weekly, of both the serum phosphate and calcium levels to determine efficacy and prevent hypercalcaemia.
If hypercalcaemia occurs, the dosage should be reduced or the treatment withdrawn temporarily, depending on the degree of hypercalcaemia. The risk of hypercalcaemia needs to be considered particularly during concomitant treatment with Vitamin D preparations.
The concomitant administration of calcium and vitamin D derivatives is to be made under the supervision of a physician.
Patients suffering with progressive renal failure may exhibit signs of, and should be warned of the symptoms of, hypercalcaemia, ectopic or vascular calcification, or adynamic bone disease. Regular monitoring is required since caution is needed in administering Phosex under these circumstances.
The long-term toxicity of Phosex has not been evaluated in clinical trials. In particular during long-term phosphate binding therapy with calcium salts there have been reports of tissue calcifications. It is not known whether the risk of calcification is higher with Phosex than with other calcium salts.
Patients should be advised to seek medical advice before taking non-prescription antacids containing calcium carbonate or other calcium salts to avoid adding to the calcium load.