title: Intravenous calcitriol lowers serum calcium concentrations in uraemic patients with severe hyperparathyroidism and hypercalcaemia.
abstract: We studied the effects of intravenous calcitriol in four persistently hypercalcaemic patients established on haemodialysis. All had marked hyperparathyroidism and had been previously shown to be intolerant to vitamin D by mouth. Calcitriol was administered at the end of each dialysis session in doses of 0.5-2.5 micrograms for 2 months and continued for 7 and 8 months in two patients. A significant decrease in serum calcium was observed after 2 weeks, which was maintained throughout treatment despite increasing the dose of calcitriol. This was associated with a decrease in serum concentrations of iPTH (28% of the initial value at 4 weeks), suggesting a shift in the set-point for PTH secretion. During longer-term treatment, serum calcium values increased, but lower concentrations of iPTH were maintained. We conclude that an increment in serum calcium is not a prerequisite for the suppressive action of calcitriol on parathyroid secretion and that the presence of hypercalcaemia does not preclude its use. Longer-term studies on a larger number of patients are required to assess the therapeutic potential of intravenous calcitriol in hypercalcaemic patients.
authors.affiliation: University of Sheffield Medical School, UK.
authors.forename: N A
authors.initials: NA
authors.lastname: Hamdy
authors.forename: C B
authors.initials: CB
authors.lastname: Brown
authors.forename: J A
authors.initials: JA
authors.lastname: Kanis
mesh_terms: D000328:Adult; D002117:Calcitriol / Q000008:administration & dosage*; D002118:Calcium / Q000097:blood*; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood / Q000209:etiology; D006961:Hyperparathyroidism / Q000097:blood / Q000150:complications; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D014511:Uremia / Q000097:blood / Q000150:complications / Q000188:drug therapy*
chemical_list: D010281:Parathyroid Hormone; D002117:Calcitriol; D002118:Calcium