A retrospective study on the safety and effectiveness of olanzapine versus midazolam for pre-hospital management of excited delirium syndrome

Objective: To evaluate the safety and effectiveness of olanzapine compared to midazolam for the pre-hospital management of excited delirium syndrome. Methods: A retrospective review of patients who were treated by ambulance crew for excited delirium syndrome from 2016 to 2019 was performed. The drug of choice was given per Fire Service Department’s paramedic protocol (intramuscular midazolam January 2016 to October 2018 and intramuscular olanzapine October 2018 to December 2019). The primary outcome was the proportion of patients experienced at least one adverse event. The secondary outcome was the successful sedation rate. Results: A total of 201 patients were included in the study. Ninety-nine patients had pre-hospital midazolam and 102 received olanzapine. Thirty-one patients experienced adverse event after arrival to A&E, including a drop of Glasgow Coma Scale score to below 8 (90%), hypotension (6%), and airway obstruction (3%): 17 (17% patients; 1 airway obstruction and 16 Glasgow Coma Scale score below 8) in midazolam group and 14 (14% patients; 2 hypotension and 12 Glasgow Coma Scale score below 8) in olanzapine group (p = 0.41). Sixty-eight patients (69%) in midazolam group achieved successful sedation, compared with 79 (77%) in olanzapine group (p = 0.20). More adverse events were seen with midazolam than olanzapine in alcohol intoxication subgroup with statistical significance (12 vs 2, p = 0.03). Conclusion: Both midazolam and olanzapine can achieve a satisfactory success rate of sedation. More adverse events are associated with midazolam use in patients with acute alcohol intoxication, especially over-sedation and airway compromise. Olanzapine would be a safer choice in the pre-hospital setting where the resource is limited, and differentiation of underlying causes is not always possible.