Quetiapine demonstrates good tolerability and is associated with improvements in extrapyramidal symptoms in patients with schizophrenia switched from other antipsychotics: results of a naturalistic study

Abstract

Objectives. Compared with conventional agents, atypical antipsychotics such as quetiapine (Seroquel®; AstraZeneca) show improved tolerability and a lower liability to cause extrapyramidal symptoms (EPS). In the routine treatment of schizophrenia, it is usual practice to consider a change of medication when the current treatment is ineffective or poorly tolerated, although few studies are available to guide clinicians. This paper reports the results from the Seroquel Method. Patient Evaluation on Changing Treatment Relative to Usual Medication (SPECTRUM) trial, a 12-week, open-label, noncomparative study that evaluated clinical benefit and tolerability of switching patients with schizophrenia from their existing antipsychotic to quetiapine. Patients were switched because of intolerance to, or lack of efficacy with, their previous antipsychotic. Quetiapine was titrated to 400 mg/day over 7 days, then dosed flexibly up to 750 mg/day over the remaining weeks (mean modal dose 505 mg/day). Results. In the overall population of 506 evaluable patients, quetiapine was well tolerated, with a low incidence of adverse events and minimal requirement for anticholinergic medication. Significant improvements in EPS, including parkinsonism and akathisia, were observed, irrespective of reason for switching, although greatest improvements were observed in patients switching because of EPS. Conclusions. This study provides further evidence for the utility and tolerability of quetiapine, in patients with schizophrenia who had been switched from a previous antipsychotic, following problems with efficacy or tolerability.