The Journal of clinical psychiatry
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Extrapyramidal symptoms and tolerability of olanzapine versus haloperidol in the acute treatment of schizophrenia.
A relative lack of extrapyramidal symptoms (EPS, i.e., the syndromes of dystonia, parkinsonism, akathisia, dyskinesia) is one criterion used to determine whether an antipsychotic is "atypical." The extrapyramidal symptom profiles of the novel antipsychotic olanzapine and the conventional antipsychotic haloperidol were compared in a population of 2606 patients from three well-controlled prospective clinical trials. ⋯ Olanzapine exhibited a statistically significantly lower extrapyramidal symptom profile than the conventional antipsychotic haloperidol at comparably effective antipsychotic doses. The lower extrapyramidal symptom profile with olanzapine was evident despite statistically significantly more frequent use of anticholinergic drugs among haloperidol-treated patients. Fewer olanzapine-treated than haloperidol-treated patients discontinued because of EPS, suggesting that olanzapine should contribute to better compliance with longer term maintenance treatment, with minimal anticholinergic-associated events.