Gallium nitrate inhibits calcium resorption from bone and is effective treatment for cancer-related hypercalcemia.
Approximately two-thirds of patients who receive the anticancer drug gallium nitrate develop mild hypocalcemia. To evaluate the mechanism of drug-induced hypocalcemia, we tested the effects of gallium nitrate upon in vitro release of 45Ca++ from explanted fetal rat bones. The drug significantly inhibited 45Ca++ release in response to stimulation with both parathyroid hormone and a lymphokine preparation with osteoclast activating factor activity. The inhibitory effects on bone resorption were both time- and dose-dependent. Later, in a pilot study, we treated 10 patients who had cancer-related hypercalcemia with gallium nitrate administered by continuous infusion. All patients responded by a reduction of total serum calcium to normal or subnormal concentrations (13.8 +/- 1.05 mg/dl, mean +/- SD pretreatment, to 8.03 +/- 1.03 mg/dl, mean posttreatment nadir). Our results indicate that gallium nitrate effectively treats cancer-related hypercalcemia and that it probably acts by inhibiting calcium release from bone.
D000818:Animals; D001862:Bone Resorption / Q000187:drug effects*; D002118:Calcium / Q000037:antagonists & inhibitors*; D002132:Calcium Radioisotopes; D005260:Female; D005708:Gallium / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D006934:Hypercalcemia / Q000150:complications / Q000188:drug therapy*; D006996:Hypocalcemia / Q000139:chemically induced; D008297:Male; D009369:Neoplasms / Q000150:complications; D010865:Pilot Projects; D011247:Pregnancy; D051381:Rats
D002132:Calcium Radioisotopes; D005708:Gallium; D002118:Calcium; C027235:gallium nitrate