Intramuscular olanzapine versus short-acting typical intramuscular antipsychotics: Comparison of real-life effectiveness in the treatment of agitation

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 (>= 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.