Correlation between steady-state plasma concentrations (Css) of bromperidol and haloperidol.

1. Bromperidol is a close structural analogue of haloperidol, and its metabolic pathways are similar to those of haloperidol. The authors studied the correlation between the Css of bromperidol and haloperidol. 2. The subjects were 16 schizophrenic inpatients. Fourteen patients received firstly bromperidol 12 mg/day and secondly haloperidol 12 mg/day, while the remaining two patients received the two treatments in the opposite sequence. 3. Blood samplings were performed 2-3 weeks after the initiation of each treatment, and the Css of bromperidol, haloperidol and their reduced metabolites were measured by high-performance liquid chromatography. 4. Neither the correlation between the Css of bromperidol and haloperidol (r = 0.246) nor that between the Css of reduced bromperidol and reduced haloperidol (r = 0.142) was significant. 5. The present study thus suggests that the Css of bromperidol and haloperidol do not correlate well in individuals.