Trifluoperazine plasma levels and clinical response.

The authors studied 36 acutely psychotic inpatients who were diagnosed as having either a schizophrenic (N = 30) or other psychotic (N = 6) disorder. After a washout phase averaging 18 days, all patients were placed on trifluoperazine 5 mg orally twice a day. Plasma levels of trifluoperazine were obtained on days 11 and 15 of treatment and then compared with clinical response. After 2 weeks of treatment an inverted U-shaped relationship was found between change scores on the Brief Psychiatric Rating Scale and trifluoperazine plasma levels.