A single-day treatment of tumor-induced hypercalcemia by intravenous amino-hydroxypropylidene bisphosphonate.

Twenty patients with malignant hypercalcemia were treated with amino-hydroxypropylidene bisphosphonate (AHPrBP, previously APD), a potent inhibitor of osteoclast-mediated bone resorption. To assess the efficacy of a single-day treatment and determine the optimal dose of this compound, all patients received AHPrBP intravenously over 24 h, but they were divided into two subsequent groups of 10 patients: Group A received a single dose of 60 mg AHPrBP and group B received a single dose of 30 mg. In both groups all patients responded to AHPrBP with a decrease in plasma calcium concentration after a mean time lag of 1 day. Within 6 days, plasma calcium (corrected for serum proteins) fell from 3.24 +/- 0.14 to 2.24 +/- 0.06 mmol/liter in group A (p less than .001), but only from 3.22 +/- 0.15 to 2.49 +/- 0.10 mmol/liter in group B (p less than .005). Whereas in all patients from group A plasma calcium was within the normal range at days 9 and 14, in 4 patients of group B it was still above the normal range at day 9, and in 5 patients at day 14. There was a significant difference in plasma calcium between group A and group B from days 5 to 14 (p less than .005). In both groups, urinary calcium excretion fell dramatically and similarly, and plasma phosphate concentration decreased significantly (p less than .01) to values slightly below the normal range from days 4 to 6.(ABSTRACT TRUNCATED AT 250 WORDS)