The efficacy of a rapid-acting intramuscular formulation of olanzapine for positive symptoms

Abstract

Rapid tranquilization of acutely psychotic patients with schizophrenia is usually carried out using typical antipsychotic agents. The objective of such treatment is to control agitation, not to treat psychosis, which usually responds only after a few weeks of treatment. An intramuscular formulation of the atypical antipsychotic olanzapine was developed for treatment of agitation in acutely psychotic patients. Studies conducted to assess control of agitation in schizophrenia also investigated the positive symptom efficacy of olanzapine when used to provide rapid tranquilization. This article summarizes the results of 3 clinical trials with intramuscular olanzapine with regard to positive symptom efficacy as measured by the Brief Psychiatric Rating Scale (BPRS; 0-6 scale) positive subscale. In 2 open-label trials, patients treated with intramuscular olanzapine experienced a mean decrease from baseline in BPRS positive subscale score. In 1 double-blind clinical trial of intramuscular olanzapine versus intramuscular haloperidol and intramuscular placebo, the mean decrease from baseline in BPRS positive subscale score for patients treated with intramuscular olanzapine was statistically significant (p < .05). In all 3 studies, positive symptom improvement continued following transition to oral olanzapine. These results suggest that intramuscular olanzapine has positive symptom efficacy early in the course of treatment and may provide a smooth transition to maintenance therapy with oral olanzapine.