A STUDY OF THE THERAPEUTIC SPECTRUM OF A FIXED-DOSE OF ZOTEPINE AND ITS RELATIONSHIP WITH SERUM CONCENTRATIONS OF THE DRUG

The therapeutic spectrum of zotepine, an antipsychotic drug, and its relationship with serum concentrations of the drug were investigated by a fixed-dose study (100 mg/day in the first week, and 200 mg/day for the next 3 weeks) in 20 schizophrenic in-patients. The mean percentages of symptom reduction.in total Brief Psychiatric Rating Scale (BPRS) and three subgroups were 63.4 per cent for total, 64.4 per cent for positive symptoms, 41.8 per cent for negative symptoms and 74.2 per cent for anxiety-depression respectively. Total, positive and negative symptoms were significantly reduced after 2 weeks (p < 0.01), while a significant reduction in anxiety-depression symptoms was already found after 1 week (p < 0.01). There were significant differences in the values of percentage improvement in total and positive symptoms after 2 weeks (p < 0.05) and negative symptoms after 1 week (p < 0.05) between responders (more than 50 per cent reduction in total BPRS scores at the end of the study) and nonresponders. In 18 patients (90 per cent), the clinical response at 2 weeks corresponded well to the final outcome. No definite relationship was found between serum zotepine concentrations and the clinical efficacy.