Relationship of butaperazine blood levels to plasma prolactin in chronic schizophrenic patients.

The relationship of plasma prolactin to plasma or red blood cell butaperazine levels was investigated in chronic schizophrenic patients treated with clinical doses of butaperazine, both after a single acute dose of the drug and during regular, twice daily butaperazine administration. Although there was a significant curvilinear relationship between peak plasma butaperazine levels after an acute single oral dose of butaperazine and the maximum prolactin response that we measured, steady-state levels of plasma or red cell butaperazine and plasma prolactin were not related. We conclude that plasma prolactin cannot be used as a substitute for or even as a rough indicator of butaperazine blood levels in chronic schizophrenic patients being treated with clinical doses of butaperazine.