A multicentre, double-blind, randomized comparison of quetiapine (ICI 204,636, 'Seroquel') and haloperidol in schizophrenia

Background. Quetiapine (ICI 204,636,'Seroquel') is a new atypical antipsych otic agent with a similar binding profile to the original atypical antipsyc hotic, clozapine. Its clinical efficacy has already been demonstrated at mu ltiple fixed doses(150-750 mg/day) and has been suggested to be comparable with haloperidol (12 mg/day). Methods. This international, 6-week, multicentre, double-blind, randomized, parallel-group trial compared quetiapine with haloperidol (455 mg and 8 mg mean total daily doses, respectively) in 448 hospitalized patients with ac ute exacerbation of chronic or subchronic schizophrenia (DSM-III-R), in ord er to establish their equivalence in terms of efficacy, and the nature of t heir tolerability profiles, especially in terms of extrapyramidal symptoms (EPS) and serum prolactin levels. Results. Both quetiapine and haloperidol produced a clear reduction in the Positive and Negative Syndrome Scale (PANSS) scores and Clinical Global Imp ression (CGI) Severity of Illness and Global Improvement scores. At day 42, the PANSS total score was reduced by - 18.7 +/- 1.63 in the quetiapine gro up, and - 22.1 +/- 1.63 in the haloperidol group (P = 0.13, between-treatme nt). Quetiapine was better tolerated than haloperidol in terms of EPS as demonst rated by the significant differences in the Simpson Scale and Abnormal Invo luntary Movement Scale scores (P < 0.05). Although patients in both groups had elevated serum prolactin concentrations at baseline, mean serum prolact in concentration decreased (by 16.5 mu g/l) in quetiapine-treated patients, yet increased (by 5.9 mu g/l) in patients treated with haloperidol. Conclusion. Quetiapine is an effective and well tolerated antipsychotic of comparable efficacy to haloperidol and lacks the latter compound's effect o n prolactin and EPS.