Certain neuroleptics reduce bone mineralization in schizophrenic patients.

A significant increase of urinary Ca and hydroxyproline levels and a decrease of urinary alkaline phosphatase activity were found in 12 schizophrenic patients receiving certain neuroleptic drugs. In these patients, the levels of active metabolites of vitamin D3 were decreased, while the levels of midmolecule parathyroid hormone were within the normal range, except for 2 cases. These results suggest that certain neuroleptics induce the increased urinary Ca excretion through suppression of active vitamin D3 formation and that chronic treatment with certain neuroleptics may induce abnormal bone mineralization.