Stanozolol in postmenopausal osteoporosis: therapeutic efficacy and possible mechanisms of action.

To assess the efficacy of the anabolic steroid stanozolol in the treatment of osteoporosis, a 29-month double-blind study was performed with 23 treated and 23 control postmenopausal osteoporotic women. Drug efficacy was assessed by serial determinations of total body calcium (TBC--total bone mass) by neutron activation analysis, regional bone mass (RBM) by single-photon absorptiometry, and by spinal roentgenograms. Total body calcium increased 4.4% from baseline values (P less than 0.01) in the treated group and remained unchanged in the control group; the difference in the change in TBC between the treated and control groups was significant (P less than 0.03). The effect of the drug on TBC persisted throughout the 29-month period. In contrast to TBC, measurements of RBM indicated no significant differences between the treated and placebo groups, suggesting a possible differential response to therapy at various skeletal sites. No new spinal compression fractures were noted in the treated group (compared with three new fractures in the control group). Assessment of serum and urine values indicated a decrease in the level of urinary calcium and an increase in the level of total urinary cyclic AMP in the treated group. These changes were observed even though the level of serum iPTH was significantly decreased during the study. An analysis of changes in bone biopsy specimens revealed no significant differences between the treated and control groups. Seventy-six percent of the treated subjects developed SGOT elevations or other side effects from the stanozolol therapy; at no time were these effects sufficiently severe to cause termination of medication. The data suggest that long-term use of stanozolol increases the net total bone mass above pretreatment levels.