Abstract
To investigate the efficacy of calcium carbonate (CaCO3) for hyperphosphatemia, hypocalcemia, metabolic acidosis and bone metabolism in patients undergoing maintenance hemodialysis, the relationship between doses of CaCO3 and various hematological parameters, bone minerals was studied. Four patients with hyperphosphatemia and hypocalcemia undergoing maintenance hemodialysis (2 men and 2 women, 46-72 years old, duration of hemodialysis: 48-133 months) took oral CaCO3 at doses of 1.0, 3.0, or 5.0g/day for 6 months. Calcium, phosphorus, alkaline phosphatase, C-PTH, calcitonin, BUN, creatinine, magnesium, PH and bicarbonate were measured at regular intervals. Bone minerals were also measured by the microdensitometry method. Bicarbonate hemodialysis was done in all patients. The dialysate calcium level was 3.5mEq/l.
Calcium increased in 2 patients but decreased in I. Phosphorus decreased dose-dependently in 3 patients, Calcium phosphorus product and alkaline phosphatase decreased dose-dependently in 3 patients. C-PTH decreased in I patient but increased in 1. Calcitonin increased in 3 patients, but after administration of CaCO3 5.0g/day for 6 months, it decreased in all patients. BUN and creatinine increased in 2 patients. Magnesium also increased in 2 patients. PH and bicarbonate remained the same in 2 patients, but decreased in the other 2. Alkalinization was not recognized in any patients. Among the bone minerals MCI increased dose-dependently in I patient, but ΔGSmin, S. GS/D and F·GS decreased in all patients.
No overall amelioration of bone metabolism was recognized. During CaCO3 administration, blood pressure remained almost stationary in all patients. No clinical or biochemical side effects were recognized in any patients during the administration of CaCO3. It was concluded that the effect of CaCO3 as a phosphate binder was dose-dependent, and below 5.0g/day, was sufficiently effective to ameliorate hyperphosphatemia. Higher doses of CaCO3 were necessary to ameliorate hypocalcemia, metabolic acidosis and bone metabolism in patients undergoing maintenance hemodialysis. Suitable doses of CaCO3 must be further investigated.
