ABSTRACT
AIM: Effective treatment of secondary hyperparathyroidism (HPTH) with intravenous (i.v.) administration of calcitriol in hemodialysis patients. PATIENTS AND METHODS: The current study evaluates the use of i.v. calcitriol dosing in relation to the severity of the HPTH in 35 hemodialysis patients with serum phosphate < 6.5 mg/dl. Arbitrarily, patients with plasma IPTH levels (intact PTH) between 288 and 576 pg/ml (288 pg/ml = four-fold the upper normal limit) were given initially 1 microg i.v. calcitriol at the end of each dialysis (group A, n = 15). Patients with IPTH between 577 and 864 pg/ml received 2 microg i.v. calcitriol (group B, n = 10) and patients with IPTH more than 865 pg/ml were given 3 - 4 microg i.v. calcitriol (group C, n = 10). As IPTH levels decreased, the dose of i.v. calcitriol was also decreased gradually. Patients were followed-up for 4 months after the end of calcitriol treatment. RESULTS: During the i.v. calcitriol treatment period, the observed plasma IPTH concentrations compared with the baseline values were significantly lower (p < 0.01 for A and B group and p < 0.05 for C group) from the sixth month onwards in group A and C and from the third month onwards in group B. At the 12th month of follow-up, all patients being off i.v. calcitriol treatment for four months, a sharp and significant increase (p < 0.01 for group A and B and p < 0.05 for group C) of plasma IPTH was recorded in all three groups of patients. Alkaline phosphatase was also gradually decreased in all studied groups. Serum Ca and P remained unchanged in most patients. CONCLUSION: In conclusion, the study presented here demonstrates that the titration of i.v. calcitriol dosage according to the severity of HPTH is an effective and safe treatment of HPTH in chronic hemodialysis patients. It also shows that parathyroidectomy could be avoided in the majority of patients with severe HPTH, if an appropriate dose of calcitriol not aggravating hyperphosphatemia is administered.
