Plasma and red cell levels of thioridazine and clinical response in schizophrenia

The relationship of plasma and red blood cell (RBC) levels of thioridazine to clinical response in schizophrenia was evaluated in a fixed-dose study. Steady-state plasma and RBC levels of thioridazine, mesoridazine, and sum of thioridazine and mesoridazine, determined by gas-liquid chromatography, were not significantly correlated with clinical response as measured by improvement on the Brief Psychiatric Rating Scale. RBC thioridazine levels were not substantially more strongly correlated with clinical response than plasma levels.