Intramuscular olanzapine: a review of its use in the management of acute agitation.

Intramuscular olanzapine (Zyprexa) is a rapid-acting atypical antipsychotic drug that is also indicated for use in patients with agitation associated with schizophrenia or bipolar mania, the focus of this review. Evidence from three well designed trials indicates that this formulation of olanzapine is at least as effective as intramuscular haloperidol or lorazepam in the treatment of patients with acute agitation associated with schizophrenia or bipolar mania, and has a faster onset of action. Although transient reductions in blood pressure and heart rate may occur in some patients administered intramuscular olanzapine, preliminary evidence of a general lack of clinical effect on the corrected QT (QTc) interval and a low incidence of extrapyramidal symptoms (EPS) is promising. The parenteral formulation of olanzapine appears to offer an effective, fast-acting and generally well tolerated alternative in the treatment of this significant behavioural problem.