Serum Concentrations of Calcitriol and PTH in Hemo-Dialysis Patients on Treatment with Calcium Carbonate

Abstract

The effects of calcium carbonate and aluminium hydroxide as phosphate binders were investigated in nine patients on chronic hemodialysis. Aluminium hydroxide, 1 g x 3, was given during four weeks followed by a period of four weeks without any phosphate binders and after this calcium carbonate. 2.5 g x 3, was introduced for four weeks. Calcium carbonate resulted in lowering of bioactive PTH in serum from 22.4 to 16.4 pM and a rise of serum calcitriol from 8.0 to 11.5 pg/ml with maintained control of phosphate and without significant difference in the calcium-phosphate product. Calcium in serum rose from 2.27 to 2.57 mM and mild hypercalcemia (less than 3.0 mM) in five of the patients could be controlled by dose reduction of calcium carbonate without losing control of serum phosphate levels. We conclude that calcium carbonate offers advantages as a phosphate binder compared to aluminium hydroxide in that it offers equal control of serum phosphate and elevates serum calcium which helps to control the hyperparathyroidism secondary to uremia.

Keywords:

• calcium
• aluminium
• PTH
• calcitriol
• phosphate
• hemodialysis
• phosphate binder.