Blockers of beta and H2 receptors and secondary hyperparathyroidism in uraemia.

The suppressive effect on PTH secretion of propranolol, a beta 1 and beta 2 blocker, and that of atenolol a specific beta 1 betablocker was compared in 24 uraemic patients not yet on dialysis in a cross over study. Although plasma PTH concentrations were comparable, plasma bicarbonate was higher with propranolol suggesting that the initial suppression of PTH secretion by propranolol was greater as a higher bicarbonate should lead to lower ionised calcium. The suppressive effect of cimetidine on PTH secretion was assessed in 12 patients on chronic haemodialysis. In the seven compliant patients there was no change in N and C terminal plasma PTH values but plasma calcitonin concentrations significantly decreased with cimetidine and returned to initial values after cimetidine was discontinued.