CALCIUM ACETATE VERSUS CALCIUM-CARBONATE - PHOSPHATE ABSORPTION STUDIES IN CHRONIC-RENAL-FAILURE

The aim of this study was to compare the alimentary phosphate-binding capacity of calcium acetate to calcium carbonate in stable chronic ren al failure patients who were not on haemodialysis. Intestinal absorpti on of phosphate and calcium was measured on three occasions in five pa tients with chronic renal failure who were not on maintenance haemodia lysis. During each test period they received either no drug, calcium c arbonate or calcium acetate (both containing Ig elemental calcium) in a randomized manner, along with a standardized meal. Intestinal conten ts were recovered after 10h by whole gut lavage, and phosphorus and ca lcium measured in meal and intestinal contents. Faecal excretion of in gested phosphorus increased from 13.85% in the absence of drug to 29.9 1% after calcium carbonate administration. Phosphorus excretion was si gnificantly higher after calcium acetate (43.92%) compared to calcium carbonate (P < 0.05). Less calcium was absorbed from calcium acetate t han from equimolar amounts of calcium carbonate (P < 0.05). In patient s with stable renal failure, calcium acetate is a better alimentary ph osphate binder than calcium carbonate and binds more phosphorus for ea ch mol of calcium absorbed.