Abstract
The effects of histamine H2-receptor antagonists on the phosphorus binding ability of calcium carbonate were examined. Serum calcium, phosphorus, alkaline phosphatase activity (ALP), parathyroid hormone (PTH) and arterial blood pH and bicarbonate were measured during treatment with histamine H2-receptor antagonists in 16 patients undergoing maintenance hemodialysis who were given calcium carbonate. Seven patients receiving histamine H2-receptor antagonists without calcium carbonate were selected as controls. In the 16 patients, serum calcium levels, ALP, PTH and arterial blood pH and bicarbonate were not significantly altered during treatment with histamine H2-receptor antagonists, but serum phosphorus levels increased significantly after four weeks (5.6±1.1mg/dl, p<0.05) and eight weeks (5.9±0.8mg/dl, p<0.005) of treatment, as compared to the pre- treatment levels (4.8±1.2mg/dl). In addition, serum phosphorus levels significantly decreased eight weeks after discontinuation of treatment with histamine H2-receptor antagonists. In the seven patients serving as controls, serum calcium and phosphorus levels did not differ to a statistically significant extent before and after treatment with histamine H2-receptor antagonists. From these results, it is suggested that histamine H2-receptor antagonists significantly affect the phosphorus binding ability of calcium carbonate. Although the mechanism remains to be elucidated, one possible explanation may be the rise in pH of gastric juice. Careful observation of changes in the surum phosphorus level is warranted in hemodialysis patients receiving calcium carbonate and histamine H2-receptor antagonists.
