Thirty-seven patients were randomized to receive intermittent cyclic
etidronate (400 mg/day oral for 2 weeks, followed by 13 weeks off treatment) or an ADFR treatment (100 micrograms/day oral
triiodothyronine for 7 days, followed by 400 mg/day
etidronate for 2 weeks and 12 weeks off treatment). Supplemental
calcium (120 mg/day) and
vitamin D3 (400 IU/day) were given throughout the study period to all patients. Biochemical analyses, iliac-crest bone biopsies, and lumbar bone mineral content (BMC) measurements were performed before and during 60 weeks of treatment. Sixteen patients in the intermittent cyclic
etidronate group and 15 in the ADFR group completed 60 weeks of treatment. Serum
alkaline phosphatase decreased from 185 (43) (mean, (SD] to 144 (35) (p less than 0.001) and from 221 (69) to 156 (43) (p less than 0.002) during intermittent cyclic
etidronate treatment and ADFR treatment, respectively, without any significant changes in renal
hydroxyproline excretion. Final resorption depth, trabecular bone activation frequency, and bone formation rate decreased significantly from 51.5 (48.4/60.0) microns (median (25%/75% quartiles] to 44.0 (39.6/46.2) microns (p less than 0.04), from 0.30 (0.17/0.62) year-1 to 0.10 (0.02/0.19) year-1 (p less than 0.03) and from 0.035 (0.020/0.081) microns3/microns2/day to 0.015 (0.002/0.025) microns3/microns2/day, p less than 0.03 respectively, during intermittent cyclic
etidronate treatment, but were unchanged during ADFR treatment. No significant changes in trabecular bone volume, bone balance per remodeling cycle, or BMC were noted in either treatment group; no evidence of
osteomalacia was found. Intermittent cyclic
etidronate treatment may be effective in preventing bone loss and in decreasing the risk of trabecular plate perforation, and thereby maintaining the integrity of bone architecture, in
postmenopausal osteoporosis.(ABSTRACT TRUNCATED AT 250 WORDS)