LACK OF VARIATION OF PLASMA BETA-ENDORPHIN AFTER CLODRONATE INFUSION IN PATIENTS WITH INCREASED BONE-RESORPTION

Twenty patients with increased bone resorption (osteoporosis, 6; Paget 's disease, 2; multiple myeloma, 5; cancer, 7) received clodronate 300 mg by 1-hr infusion for 7 days. There was a significant decrease in s erum calcium, alkaline phosphatase, and urinary hydroxyproline in all patients, and a prompt improvement of bone pain occurred concomitantly . No significant changes in circulating beta-endorphin concentration d uring the week of therapy were observed. Changes in the beta-endorphin concentrations were evaluated by a 2-hr period of blood sampling duri ng and after the drug infusion and by daily determinations. Data sugge st that the clodronate-induced analgesic effect is probably due to a p eripheral action on osteoclasts in absence of any central effect.