[Therapeutic effect and plasma level of thioridazine in schizophrenic patients (author's transl)].

1. In 18 Patients the plasma concentration of the neuroleptic drug thioridazine was measured twice a week by a fluorometric method during a period of treatment lasting for an average of 27 days. At the same time the psychopathological findings were recorded by means of the AMP system. 2. A significant correlation was found both between dosage per kg body weight and plasma level, and between age and plasma level. No connection with the sex of the patient could be demonstrated. 3. A curve-linear correlation appears to exist between plasma concentration and remission of symptoms. 4. In the course of the trial the plasma concentrations of thioridazine declined though the dosage was kept constant. This observation indicates an increased metabolism of the drug probably brought about by enzyme induction. In two cases where previous liver damage could be assumed, the plasma concentrations were found to be above the average level.