High-dose Quetiapine for the Treatment of Schizophrenia with Inadequate Response to Quetiapine 600 mg/day

Abstract

Objectives: In this study, we aimed to determine the efficacy of high-dose quetiapine (≧800 mg/day) for Taiwanese patients with schizophrenia and with inadequate response to quetiapine 600 mg/day of more than 4 weeks. Methods: The study was a six-week, open-label study. We assessed patients' treatment response and side effects with clinical global impression-severity (CGI-S), brief psychiatric rating scale (BPRS), and extrapyramidal syndrome rating scale (ESRS). Results: Six patients participated in this study. After this six-week study, the mean dose of quetiapine was 1000 mg/day. The mean scores of BPRS and CGI-S were improved from 44.2±5.5 to 35.5±18.1 (p=0.344) and 4.7±0.8 to 3.7±1.8 (p=0.084), respectively. Four patients met the criteria of treatment responder and no patients suffered from severe adverse events. Conclusion: Although no significant statistical differences in this study were observed due to small sample size, the improvements of mean total scores of BPRS and CGI-S were 19.7% and 21.3%, respectively, and 66.7% of the patients met treatment responder criteria. For Taiwanese patients with schizophrenia and with inadequate treatment response to quetiapine 600 mg/day, we suggest that high-dose quetiapine can be effective and tolerable.