Fluphenazine plasma levels and clinical response.

Plasma levels of fluphenazine and clinical response were examined in 19 inpatient schizophrenics (DSM-III diagnoses) using a constant dose, steady-state methodology. A significant curvilinear correlation was demonstrated between clinical response and steady-state plasma levels of fluphenazine (p less than .05). A therapeutic range of plasma fluphenazine is suggested in the range of .13-.70 ng/ml. The lowest plasma level detected (.13 ng/ml) appeared to be well within the therapeutic range. The 9 patients with plasma fluphenazine levels in this range demonstrated a mean clinical improvement of 59% compared to 34% for patients with plasma levels above .70 ng/ml (p less than .01).