Intramuscular olanzapine for agitated patients: A systematic review and meta-analysis of randomized controlled trials

We performed an updated systematic review and meta-analysis of randomized controlled trials (RCTs) of intramuscular (IM)-olanzapine (OLA-IM) versus controls in agitated patients. The risk ratio, number-needed-to-treat/harm, and standardized mean difference based on a random effects model were calculated. We identified 13 RCTs (19 comparisons) as follows: 7 comparisons with 1059 patients for OLA-IM versus placebo; 5 comparisons with 613 patients for OLA-IM versus haloperidol (HAL)-IM; 2 comparisons with 108 patients for OLA-IM versus ziprasidone (ZIP)-IM; 2 comparisons with 110 patients for OLA-IM versus HAL-IM plus midazolam; and 3 comparisons with 412 patients for OLA-IM versus HAL-IM plus promethazine, 2 comparisons with 355 patients for OLA-IM versus lorazepam-IM (LOR-IM); and 1 comparison with 67 patients for OLA-IM versus HAL-IM plus LOR-IM. OLA-IM was superior to placebo in both Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) and Agitation-Calmness Evaluation Scale (ACES) scores 2 h after first injection, and had a comparable side effect profile, including over sedation, extrapyramidal symptoms, akathisia, and anticholinergic use. While there was no significant difference in PANSS-EC scores after 2 h between OLA-IM and HAL-IM, OLA-IM outperformed HAL-IM in ACES after 2 h. Compared with HAL-IM, OLA-IM was associated with fewer side effects, including anticholinergic use, akathisia, extrapyramidal symptoms, and dystonia, and marginally less QT prolongation compared with HAL-IM. Based on our findings, OLA-IM is preferable to HAL-IM for the treatment of agitated patients. However, comparator data for ZIP-IM, LOR-IM and HAL-IM combination therapy were insufficient.