A Prospective Study of Intramuscular Droperidol or Olanzapine for Acute Agitation in the Emergency Department: A Natural Experiment Owing to Drug Shortages

Study objective: Intramuscular medications are commonly used to treat agitation in the emergency department (ED). The purpose of this study is to compare intramuscular droperidol and olanzapine for treating agitation. Methods: This was a prospective observational study of ED patients receiving intramuscular droperidol or olanzapine for acute agitation. The treating physician determined the medication and dose; however, over time drug shortages made either olanzapine (July to September 2019) or droperidol (November 2019 to March 2020) unavailable, creating a natural experiment. The primary outcome was time to adequate sedation, assessed by the Altered Mental Status Scale (AMSS), defined as time to AMSS score less than or equal to 0. Results: We analyzed 1,257 patients (median age 42 years; 73% men); 538 received droperidol (median dose 5 mg) and 719 received olanzapine (median dose 10 mg). The majority of patients (1,086; 86%) had agitation owing to alcohol intoxication. Time to adequate sedation was 16 minutes (interquartile range 10 to 30 minutes) for droperidol and 17.5 minutes (interquartile range 10 to 30 minutes) for olanzapine (absolute difference –0.7 minutes; 95% confidence interval –2.1 to 0.5 minutes). Adjusted Cox proportional hazard model analysis revealed no difference between groups in time to sedation (hazard ratio for adequate sedation for droperidol compared with olanzapine 1.12; 95% confidence interval 1.00 to 1.25). Patients receiving olanzapine were more likely to receive additional medications for sedation (droperidol 17%; olanzapine 24%; absolute difference –8% [95% confidence interval –12% to –3%]). We observed no difference between drugs regarding adverse effects except for extrapyramidal adverse effects, which were more common with droperidol (n=6; 1%) than olanzapine (n=1; 0.1%). Conclusion: We found no difference in time to adequate sedation between intramuscular droperidol and olanzapine.