Effects of weekly administration of maxacalcitol therapy on secondary hyperparathyroidism in three patients on continuous ambulatory peritoneal dialysis

Maxacalcitol therapy was applyed for treatment of secondary hyperparathyroidism associated with an intact parathyroid hormone (intact-PTH) level higher than 500pg/mL in three patients on peritoneal dialysis. The patients were one male and two females aged 51.3 years on average. The mean duration of dialysis was 5.7 years and all patients had been maintained on CAPD alone. Intravenous administration of maxacalcitol was initiated with a single dose of 10μg weekly. When the intact-PTH level failed to decrease, the dose was increased gradually to a maximum dose of 30μg by 10μg per week, and then was adjusted to maintain the intact-PTH level between 100pg/mL and 250pg/mL. The intact-PTH level decreased in all patients. Levels of osteocalcin and bone alkaline phosphatase, a bone formation marker, also decreased. However, maxacalcitol therapy was discontinued in one patient who showed an increased intact-PTH level after the dose of the drug was reduced due to hypercalcemia, and in another patient who developed an increase of CPK in association with neurological symptoms of numbness. As reported above, treatment with maxacalcitol was effective in controlling secondary hyperparathyroidism in CAPD patients, but it is necessary to pay careful attention to adverse reactions such as an increase in CPK especially after reduction of dose.