Efficacy and tolerability of quetiapine in poorly responsive, chronic schizophrenia.

With the notable exception of clozapine, there is at present insufficient information on the efficacy of atypical antipsychotic medications in patients with poorly responsive schizophrenia. The present study reports on the efficacy and tolerability of quetiapine and haloperidol in patients with schizophrenia who showed no response to treatment with fluphenazine. This study is a post hoc subanalysis of an 8-week, double-blind study of patients receiving quetiapine 600 mg/day or haloperidol 20 mg/day. The proportion of patients classified as "Clinical Global Impression responders" (defined as Clinical Global Impression Severity of Illness score of < or = 3 at study end) was greater in the quetiapine group compared with the haloperidol group (51% vs. 25%; P = 0.023). Overall, quetiapine was well tolerated with less extrapyramidal side-effects and reduction in prolactin when compared to haloperidol. Weight gain was modest but more apparent in quetiapine-treated patients. Quetiapine is an appropriate treatment choice in patients who do not respond to prior antipsychotic treatment.