Substitution of aluminium salts by magnesium salts in control of dialysis hyperphosphataemia.

For two years all 28 patients undergoing hospital haemodialysis were switched from a dialysate magnesium (Mg) of 0.85 mmol/l to one containing none. Oral aluminium hydroxide was discontinued, and magnesium carbonate was substituted as a phosphate binder. After 24 months on this regimen predialysis aluminium concentration had fallen significantly. There was no significant change in predialysis phosphate, which remained above the normal range; nor was there evidence of increased secondary hyperparathyroidism as judged by parathyroid hormone immunoassay and biochemical or clinical criteria. Predialysis Mg concentrations tended to fall towards the normal range. Aluminium-containing phosphate binders seem to be unnecessary for the control of dialysis hyperphosphataemia. Magnesium carbonate may be an alternative and less toxic compound.