The Efficacy of a Rapid-Acting Intramuscular Formulation of Olanzapine for Positive Symptoms

Rapid tranquilization of acutely psychotic patients with schizophrenia is usually carried out usingtypical 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 ofthe atypical antipsychotic olanzapine was developed for treatment of agitation in acutely psychoticpatients. Studies conducted to assess control of agitation in schizophrenia also investigated the positivesymptom efficacy of olanzapine when used to provide rapid tranquilization. This article summarizesthe results of 3 clinical trials with intramuscular olanzapine with regard to positive symptom efficacyas measured by the Brief Psychiatric Rating Scale (BPRS; 0-6 scale) positive subscale. In 2open-label trials, patients treated with intramuscular olanzapine experienced a mean decrease frombaseline in BPRS positive subscale score. In 1 double-blind clinical trial of intramuscular olanzapineversus intramuscular haloperidol and intramuscular placebo, the mean decrease from baseline inBPRS positive subscale score for patients treated with intramuscular olanzapine was statistically significant(p < .05). In all 3 studies, positive symptom improvement continued following transition tooral olanzapine. These results suggest that intramuscular olanzapine has positive symptom efficacyearly in the course of treatment and may provide a smooth transition to maintenance therapy with oralolanzapine.