Effects of high doses of corticosteroids on bone metabolism.

The effects of a chronic treatment with corticosteroids on bone are well known, but few data are available regarding the acute effect of these drugs on bone turnover. This study was aimed at evaluating the effects of high doses of corticosteroids administered for a short period on bone metabolism. We assessed 23 subjects (15 women and 8 men) suffering from multiple sclerosis and treated with methylprednisolone (1 g i.v. for 10 days) followed by oral prednisone for 9 days; patients affected by diseases involving bone or treated during the previous 6 months with drugs influencing bone metabolism were excluded. We observed a significant decrease of ALP and bone glia protein (BGP), in these subjects, and a significant sudden increase of urinary calcium/creatinine and urinary cross-laps after 3 days of treatment. All of these parameters, except urinary calcium/creatinine, returned to basal levels after 30 days from the beginning of treatment (11 days after the interruption of corticosteroids administration). Serum phosphorus showed a significant decrease after 3 days of treatment, but returned to basal levels after 10 days. These data suggest that high doses of corticosteroids administered for a short period are able to induce an increase of bone resorption and a decrease of bone formation; moreover, bone turnover returns to basal levels when the treatment is stopped.