Quetiapine ('Seroquel'); an effective and well-tolerated atypical antipsychotic.

Antipsychotic drugs are the mainstay of treatment of patients with schizophrenia. These drugs cause many side-effects, of which the most problematic are extrapyramidal symptoms. This paper reviews published preclinical and clinical studies on quetiapine, a new atypical antipsychotic. The preclinical studies predict a low risk of extrapyramidal symptoms, and this is borne out in clinical trials in patients with relapses of moderate or severe schizophrenia. Indeed, the occurrence of extrapyramidal symptoms with quetiapine is indistinguishable from that with placebo across the dose range. In general, quetiapine is well tolerated, producing side-effects no worse than those encountered with standard antipsychotics. With regard to efficacy, quetiapine appears as effective as the older antipsychotics haloperidol and chlorpromazine in treating schizophrenia. Quetiapine thus offers the clinician a significant advance over standard antipsychotic drugs.