Cimetidine and circulating calciotropic hormone levels in uremic patients: evidence for a suppressive effect on calcitonin secretion.

The effect of oral cimetidine on parathyroid hormone and calcitonin plasma levels was evaluated in 12 uremic patients on chronic hemodialysis. Compliance to treatment was monitored by measuring cimetidine plasma concentrations. Plasma cimetidine was measurable in 7 patients and undetectable in 5. In compliant patients, there was no change in plasma concentration of calcium and parathyroid hormone but a significant fall of 75% in plasma calcitonin levels during treatment, followed by an increase towards initial values after cimetidine discontinuation. No significant change occurred in the other 5 patients. Cimetidine therefore appears to be of little value in the treatment of uremic hyperparathyroidism.