title: Failure of cimetidine to affect calcium homeostasis in familial primary hyperparathyroidism (multiple endocrine neoplasia, type 1).
abstract: Recent reports that cimetidine, a blocker of histamine H2 receptors, lowered serum calcium and/or immunoreactive parathyroid hormone (PTH) concentrations in primary or secondary hyperparathyroidism prompted us to administer the drug (300 mg, orally, every 6 h) to two patients with hyperparathyroidism accompanying familial multiple endocrine neoplasia type 1. The patients were hypercalcemic (10.9--11.2 mg/dl), hypophosphatemic (2.0--2.4 mg/dl), and hypercalciuric (greater than or equal to 410 mg/24 h), with elevated urinary cAMP and phosphate clearance and inappropriately high serum immunoreactive PTH levels. Multiple observations of these variables over 5 weeks of cimetidine treatment showed no systematic changes; in particular, serum and urinary calcium did not change, and there was no evidence of a decreased PTH effect on the kidneys. The data offer no support for the treatment of familial hyperparathyroidism with cimetidine.
mesh_terms: D000293:Adolescent; D000328:Adult; D002118:Calcium / Q000378:metabolism*; D002927:Cimetidine / Q000627:therapeutic use*; D003404:Creatinine / Q000378:metabolism; D005260:Female; D006146:Guanidines / Q000627:therapeutic use*; D006706:Homeostasis; D006801:Humans; D006961:Hyperparathyroidism / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009377:Multiple Endocrine Neoplasia / Q000188:drug therapy / Q000378:metabolism; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000378:metabolism
chemical_list: D006146:Guanidines; D010281:Parathyroid Hormone; D010758:Phosphorus; D002927:Cimetidine; D003404:Creatinine; D002118:Calcium