An integrated analysis of acute treatment-emergent extrapyramidal syndrome in patients with schizophrenia during olanzapine clinical trials: comparisons with placebo, haloperidol, risperidone, or clozapine.J Clin Psychiatry. 2003 Aug; 64(8):898-906.JC
The frequency and severity of extrapyramidal syndrome (EPS) were evaluated in patients with DSM-III or DSM-IV schizophrenia in the acute phase (- 8 weeks) of randomized, double-blind, controlled trials from the integrated olanzapine clinical trial database.
This retrospective analysis included 23 clinical trials and 4611 patients from November 11, 1991, through July 31, 2001. Incidences of dystonic, parkinsonian, and akathisia events were compared using treatment-emergent adverse-event data. Categorical analyses of Simpson-Angus Scale and Barnes Akathisia Scale (BAS) scores, use of anticholinergic medications, and baseline-to-endpoint changes in Simpson-Angus Scale and BAS scores were compared.
A significantly smaller percentage of olanzapine-treated patients experienced dystonic events than did haloperidol- (p <.001) or risperidone-treated patients (p =.047). A significantly greater percentage of haloperidol-treated patients experienced parkinsonian (p <.001) and akathisia (p <.001) events than did olanzapine-treated patients. Categorical analysis of Simpson-Angus Scale scores showed significantly more haloperidol- (p <.001) or risperidone-treated patients (p =.004) developed parkinsonism than did olanzapine-treated patients. Olanzapine-treated patients experienced significantly greater reductions in Simpson-Angus Scale scores than did haloperidol- (p <.001), risperidone- (p <.001), or clozapine-treated (p =.032) patients. Categorical analysis of BAS scores showed significantly more haloperidol-treated patients experienced treatment-emergent akathisia versus olanzapine-treated patients (p <.001). Significantly greater reductions in BAS scores were experienced during olanzapine treatment versus placebo (p =.007), haloperidol (p <.001), and risperidone (p =.004) treatments. A significantly smaller percentage of olanzapine-treated patients received anticholinergic medications compared with that of haloperidol- (p <.001) or risperidone-treated patients (p =.018). Compared with that in olanzapine-treated patients, the duration of anticholinergic cotreatment was significantly longer among haloperidol- (p <.001) or risperidone-treated patients (p =.040) and significantly shorter among clozapine-treated patients (p =.021).
This analysis of available data from olanzapine clinical trials lends additional support to olanzapine's favorable EPS profile.