RED-BLOOD-CELLS HALOPERIDOL REDUCTASE-ACT IVITY - INTEREST IN THE INITIATION OF HALOPERIDOL TREATMENT

Serum levels of haloperidol and reduced haloperidol as well as the red uced haloperidol/haloperidol ratios were determined in nine acute schi zophrenics on oral haloperidol medication and correlated over 21 days with psyche pathology and extra-pyramidal symptom scores. We have inve stigated red blood cells haloperidol reductase activity in the group o f patients. Significant correlations were found between haloperidol pl asma levels and positive sub scale for each patient (r = 0,86 and p < 0,01; r = 0,70 and p c 0,05). We found a correlation between red blood cells reductase activity and the improvement of the psychotic anxiety scale (r = 0,64/and p < 0,05; r = 0,67 and p < 0,05), but not with re duced haloperidol/haloperidol ratios in plasma. The knowledge of reduc tase activity could predict the treatment response in acute schizophre nic patients. We suggest that the reported inter individual and inter ethnic differences in haloperidol and reduced haloperidol and in clini cal response and adverse effects may be a reflection of genetic contro l of the two oxidative pathways mediated by cytochrome P450 isozyme an d/or the reductase pathway mediated by haloperidol reductase in indivi dual subject.