Effective treatment of secondary hyperparathyroidism in hemodialysis patients by titration of intravenous calcitriol dosage

Aim: Effective treatment of secondary hyperparathyroidism (HPTH) with intra venous (i.v.) administration of calcitriol in hemodialysis patients. Patien ts and methods: The current study evaluates the use of i.v. calcitriol dosi ng 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 no rmal limit) were given initially 1 ug i.v. calcitriol at the end of each di alysis (group A, n = 15). Patients with IPTH between 577 and 864 pg/ml rece ived 2 mu g i.v. calcitriol (group B, n = 10) and patients with IPTH more t han 865 pg/ml were given 3 - 4 mu g i.v. calcitriol (group C, n = 10). As I PTH levels decreased, the dose of i.v, calcitriol was also decreased gradua lly. Patients were followed-up for 4 months after the end of calcitriol tre atment. Results: During the i.v. calcitriol treatment period, the observed plasma IPTH concentrations compared with the baseline values were significa ntly lower (p < 0.01 for A and B group and p < 0.05 for C group) from the s ixth month onwards in group A and C and from the third month onwards in gro up B. At the 12th month of follow-up, all patients being off i.v. calcitrio l 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 decrease d 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 a n effective and safe treatment of HPTH in chronic hemodialysis patients. It also shows that parathyroidectomy could be avoided in the majority of pati ents with severe HPTH, if an appropriate dose of calcitriol not aggravating hyperphosphatemia is administered.