Abstract
We observed a significant lowering of plasma inorganic phosphorus (p<0.01) and elevation of plasma calcium (p<0.01) with the correction of metabolic acidosis (p<0.01) after calcium carbonate (3g daily) administration over 2 weeks in 20 outpatients undergoing hemodialysis. Calcium carbonate was successfully effective in the majority of patients and vitamin D or calcium carbonate was stopped or reduced to avoid hypercalcemia and alkalemia within 2-4 weeks after the administration of calcium carbonate, but calcium carbonate was not effective in 2 patients who retained a high plasma phosphorus level above 8mg/dl. There was a significant correlation between the decrease in plasma phosphorus and the increase in plasma calcium (r=0.47, p<0.05). This correlation was especially significant in the group of patients not prescribed vitamin D (r=0.77, p<0.05). The decrease in plasma phosphorus was larger in the group of patients not prescribed vitamin D than in the prescribed group. Thus calcium carbonate is an effective phosphorus binder and is also a source of calcium supplementation and alkali. In addition, there were fewer gastrointestinal symptoms compared with those produced by aluminum hydroxidegel.
Continuous administration of calcium carbonate, however, caused some problems (itching, feeling of fainting etc.) due to hypercalcemia and/or alkalemia, and some contradictions with usual dialysis therapy involving dosage of vitamin D, calcium concentration of dialysate etc.. We feel that calcium carbonate could be confidently given to most hemodialysis patients for control of plasma calcium, phosphorus and acidosis with close and continuous monitoring of plasma biochemical parameters.
In conclusion, a new therapeutic manipulation for dialysis by administration of the calcium carbonate, vitamin D preparation, calcium concentration in the dialysate and the withholding of aluminum containing compounds is urgently required.
