Objective: The authors evaluated the comparative efficacy and safety of intramuscular olanzapine, intramuscular haloperidol, and intramuscular placebo for the treatment of acute agitation in schizophrenia.
Method: Hospitalized patients with schizophrenia received one to three injections of intramuscular olanzapine, 10 mg, intramuscular haloperidol, 7.5 mg, or intramuscular placebo over a 24-hour period. Agitation was measured with the excited component of the Positive and Negative Syndrome Scale and two additional scales.
Results: According to scores on the excited component of the Positive and Negative Syndrome Scale, both intramuscular olanzapine and intramuscular haloperidol reduced agitation significantly more than intramuscular placebo 2 and 24 hours following the first injection. Intramuscular olanzapine reduced agitation significantly more than intramuscular haloperidol 15, 30, and 45 minutes following the first injection. No patients treated with intramuscular olanzapine experienced acute dystonia, compared with 7% of those who were treated with intramuscular haloperidol. No significant QT(c) interval changes were observed in any patients.
Conclusions: Intramuscular olanzapine represents a rapid, effective, and safe treatment for acute agitation in schizophrenia.