A Prospective Observational Study of Patients Receiving Intravenous and Intramuscular Olanzapine in the Emergency Department

Study objective Parenteral olanzapine is an emerging therapy for a variety of conditions in the emergency department (ED). Intramuscular administration is standard; however, intravenous administration has been proposed as a safe alternative route. We investigate the safety and efficacy of both intramuscular and intravenous olanzapine in the ED when used for a variety of indications. Methods This was a prospective observational study of patients presenting to an urban Level I trauma center ED. Trained research associates screened the ED for patients receiving parenteral olanzapine. The primary outcome of the study was incidence of respiratory depression measured with standard markers. Secondary outcomes included use of additional doses or sedatives, corrected QT interval (QTc) data, time to nadir sedation, adverse events, and physician assessment of efficacy. Results There were 784 patients included in the final analysis. Intravenous olanzapine was administered to 295 patients; 489 received intramuscular olanzapine. Respiratory depression occurred in 11 of 295 patients (3.7%; 95% confidence interval [CI] 1.6% to 5.9%) receiving intravenous olanzapine and 10 of 489 (2.0%; 95% CI 0.8% to 3.3%) receiving intramuscular olanzapine. Seven patients required intubation, 2 in the intravenous group and 5 in the intramuscular group. Nonrespiratory complications occurred in 8 patients, 6 of 295 (2.0%; 95% CI 0.4% to 3.6%) in the intravenous group and 2 of 489 (0.4%; 95% CI 0% to 0.96%) in the intramuscular group. Dysrhythmias were isolated to 2 episodes of bradycardia requiring only supportive care. Conclusion These data suggest that, with proper monitoring, administration of olanzapine, both intramuscular and intravenous, is safe for several indications in the ED.