INCREASING BONE-DENSITY IN MYELOMA PATIENTS AFTER THE ADMINISTRATION OF CLODRONATE

The use of bisphosphonates in hypercalcemia is fully accepted, but the long term therapy with bisphosphonates is still controversial. The ai m of our study was to evaluate the influence of clodronate on the bone density of myeloma patients. 20 patients were included in the study. A total dose of 3000 mg clodronate was administered in 4 to 6 hourly i nfusions of 600 mg a day, once in 3 months. The effect of clodronate o n bone density was evaluated by CT-densitometry over a period of 6 mon ths. At the beginning of May 1994, 15 patients had completed at least 2 estimations of bone density. The amount of hydroxyapatite had increa sed in 9 patients, remained unchanged in 1 of them, and decreased in 4 of them during the 6 months. The mean bone density before the adminis tration of clodronate was -2.6 SD (standard deviation of European stan dard bone density for the respective age and sex). After 6 months of t herapy, bone density had increased to -2,3 SD. The mean amount of hydr oxyapatite in spongiosa rose from the mean value of 32.71 mg/ml before clodronate administration to 38.91 mg/ml after the 6-month treatment period. The mean increase in calciumhydroxyapatite in trabecular bone mass was 6.2 mg. Clodronate contributed to alleviating bone pain in th e majority of patients, but this effect is difficult to evaluate becau se of other treatment modalities administered concomitantly. The toler ance of clodronate was very good. No impairments of renal function, no r other adverse effects were observed. Only in 2 patients the decrease in calcium concentration caused slight tetania. Therefore, close moni toring of the calcium level and peroral substitution of calcium in the case of its decrease below the physiological level is recommended.