Objective: To compare the effectiveness of intramuscular (IM) olanzapine and typical IM antipsychotics in naturalistically treated acutely agitated patients with schizophrenia or acute mania.
Methods: During the acute phase, 2011 inpatients (including emergency settings) were assessed at 2, 24 and 72 h, and 7 days following initial injection and on oral antipsychotic transition. Mean change in agitation was assessed via Positive and Negative Symptom Scale-Excited Component (PANSS-EC) and Clinical Global Impressions-Severity (CGI-S) scores. Response (> or = 40% reduction in baseline PANSS-EC score) was analysed using logistic regression.
Results: Significantly greater decreases in PANSS-EC and CGI-S scores were observed in patients receiving IM olanzapine (n = 1294) as their first injection compared with patients receiving other IM antipsychotics (n = 717) (P<0.05; 2 h: effect size 0.1); IM haloperidol treatment (all assessments, P<0.05); and IM zuclopenthixol treatment (2 h, P<0.001). Higher response rates were observed with IM olanzapine compared with other IM antipsychotics at 24 and 72 h, and 7 days (P<0.05). IM olanzapine was associated with fewer extrapyramidal side effects compared with other assessed IM antipsychotics.
Conclusions: IM olanzapine provided somewhat more effective control of acute agitation than other assessed IM antipsychotics.