Bone metabolism after cinacalcet administration in patients with secondary hyperparathyroidism.
Cinacalcet, an allosteric modulator of a calcium (Ca)-sensing receptor, significantly suppresses parathyroid hormone (PTH) secretion and bone turnover rate in chronic hemodialysis (HD) patients with secondary hyperparathyroidism (SHPT). In this study, bone metabolism after cinacalcet treatment was examined, because hungry bone syndrome is sometimes experienced after parathyroidectomy in severe SHPT. We conducted a prospective observational study in 17 HD patients with SHPT. Cinacalcet was started at 25 mg/day, and the dose was increased step by step based on serum calcium level. A significant decrease in serum Ca and intact PTH concentration was found within 2 weeks. Tartrate-resistant acid phosphatase 5b, a good bone resorption marker, was significantly decreased at week 2 of the study. Serum bone alkaline phosphatase, a marker of bone formation, was increased at week 2 compared with the basal level. It became, however, gradually decreased until week 14. Only one patient whose bone turnover was considerably high had a mild numbness feeling. These results suggest that cinacalcet treatment might transiently accelerate bone formation with rapid suppression of bone resorption. This uncoupling could be involved in a mechanism by which cinacalcet decreases serum Ca level.
Yano
Shozo
S
Department of Internal Medicine 1, Shimane University Faculty of Medicine, Izumo, Japan. syano@med.shimane-u.ac.jp
Suzuki
Keiko
K
Sumi
Masaaki
M
Tokumoto
Akihide
A
Shigeno
Kazushi
K
Himeno
Yasutoshi
Y
Sugimoto
Toshitsugu
T
D000135:Acid Phosphatase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood; D001861:Bone Regeneration / Q000187:drug effects; D016723:Bone Remodeling / Q000187:drug effects*; D001862:Bone Resorption / Q000517:prevention & control; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism*; D002118:Calcium / Q000097:blood; D000069449:Cinacalcet; D004334:Drug Administration Schedule; D005260:Female; D006727:Hormone Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000378:metabolism* / Q000628:therapy; D007527:Isoenzymes / Q000097:blood; D008297:Male; D008875:Middle Aged; D009281:Naphthalenes / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D010281:Parathyroid Hormone / Q000037:antagonists & inhibitors* / Q000097:blood; D010758:Phosphorus / Q000097:blood; D006435:Renal Dialysis; D000071681:Tartrate-Resistant Acid Phosphatase; D013997:Time Factors
D015415:Biomarkers; D006727:Hormone Antagonists; D007527:Isoenzymes; D009281:Naphthalenes; D010281:Parathyroid Hormone; D010758:Phosphorus; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D002118:Calcium; D000069449:Cinacalcet