[Medium- and long-term effects of various treatment schedules with nasal S-calcitonin spray]

188 patients with high-turnover type post-menopausal osteoporosis were treated for 18 months with 4 different treatment regimens of S-calcitonin nasal spray. For a total of 18 months group 1 was given 100 IU/day, continuously; group 2, 100 IU/day daily for 30 days every other month ("ciclically"); group 3, 200 IU/day continuously, and group 4, 200 IU/day, ciclically. To monitor the effects of treatment, MOC of L2-L4, as well as serum osteocalcin and urinary hydroxyproline: creatinine levels were measured, on initiation of therapy, then at 9, 12 and 18 months, and finally at 6 and 12 months after completion of therapy. Analysis of the results yields the following major points: (A) The peak increase in bone mass occurs at 9 months the continuous therapy groups, and at 18 months in the cyclic therapy groups. In absolute values, the peak are higher in the continuous groups than in the cyclic groups. (B) The long-term increase in bone mass (measured at one year after completion of therapy) does not differ significantly between cyclic and continuous treatment groups at the same dosage. (C) During treatment, a dose-effect relationship exist when comparing dosages of 100 IU/day and 200 IU/day. However, this disappears by one year after completion of therapy. (D) There seems to be a "rebound effect" on osseous turnover after cessation of S-calcitonin therapy. The magnitude and rapidity of onset of this effect appear to correlate directly with the dosage of S-calcitonin administered.