EFFECT OF RECTAL SALMON-CALCITONIN TREATMENT ON BONE MASS AND BONE TURNOVER IN PATIENTS WITH ESTABLISHED POSTMENOPAUSAL OSTEOPOROSIS - A 1-YEAR CROSSOVER STUDY

A new suppository formulation of salmon calcitonin (sCT) is now availa ble to increase the choices for the clinician in the treatment of oste oporotic patients. To test this new formulation, we studied the effica cy and tolerability of rectal sCT in 40 patients with postmenopausal o steoporosis. According to a double-blind, placebo-controlled design, t he patients were divided into two groups and treated with a daily dose of 100 IU of sCT administered by suppository or matching placebo for 6 months. After 6 months, patients were crossed over so that the sCT-t reated group received placebo for the subsequent 6 months and vice ver sa. Bone mineral density (BMD), measured at the distal radius by dual photon absorptiometry and at the lumbar spine by dual energy X-ray abs orptiometry, increased by 3.3% and 3.0%, respectively, after 6 months in the sCT-treated group. The placebo group showed a significant (P < 0.05) decrease only at the lumbar spine. The differences between the t wo groups were significant, as determined by one-way analysis of varia nce. After the crossover period, only the group receiving the active t reatment showed an increase in BMD. No significant changes were observ ed in the biochemical indexes of bone turnover (serum osteocalcin and hydroxyproline/creatinine ratio) in both groups, although during the s CT treatment periods a reduction of bone turnover rate was observed, a s demonstrated by the reduction of these markers. This new formulation was well tolerated. Our results indicate that a 6-month treatment wit h sCT, at a daily dose of 100 IU administered by suppositories, is abl e to increase bone mass and to exert an inhibitory effect on bone turn over.