2025 Southeastern Residency Conference

Title: Efficacy of Olanzapine versus Quetiapine for ICU Related Agitation and Delirium 
 
Authors: Nina Casanova, Trisha Sharma, Jasleen Bolina, Neha Naik, Sagar Dave, Tu-Trinh Tran 
 
Background: Agitation and delirium are estimated to occur in 80% of critically ill patients admitted to the hospital; however, there is no gold standard of treatment. Initial management involves non-pharmacologic interventions and minimizing modifiable risk factors. While there is limited literature comparing atypical antipsychotics, critically ill patients experiencing agitation and delirium may benefit from their short-term use. This study aims to compare and evaluate the efficacy of olanzapine and quetiapine to treat agitation and delirium in the intensive care unit (ICU). 
 
Methods: This retrospective cohort analysis evaluated patients receiving either olanzapine or quetiapine for at least 24 hours with an indication of agitation, sedation, or anxiety. The study population included patients who were admitted to either a medical or surgical ICU at a tertiary medical center between August 1, 2022 and April 1, 2024. Patients were excluded if antipsychotic therapy was initiated prior to ICU admission or as a continuation of home therapy, if their antipsychotic was ordered as needed, or if they were pregnant or incarcerated. The primary outcome was the duration of delirium while on the antipsychotic, validated via CAM-ICU scores. Secondary outcomes included ICU length of stay, antipsychotic therapy duration, and incidence of antipsychotic discontinuation prior to ICU discharge. Patient and hospital course characteristics were described using medians and interquartile ranges (IQR) for continuous variables and percentages for categorical variables.  
 
Results: A total of 442 patients were reviewed for analysis. Data from 200 patients were analyzed, including 87 who received olanzapine and 113 who received quetiapine. Baseline characteristics were similar between the two groups. Risk factors for delirium prior to antipsychotic initiation included acute kidney injury (47% in olanzapine group vs. 52% in quetiapine group), alcohol use (14% vs. 12%), psychiatric diagnosis (20% vs. 19%), and prior benzodiazepine use at home (7% vs. 4%). The average duration of delirium was 5 days in both groups (p=0.447). The duration of antipsychotic therapy was similar in both groups at a median of 9 days for olanzapine and 8 days for quetiapine (p=0.510). Although a greater number of patients receiving quetiapine were mechanically ventilated at baseline than those receiving olanzapine, there was no statistically significant difference in overall duration of mechanical ventilation (64% vs. 44%). ICU length of stay was shorter for patients in the olanzapine group compared to the quetiapine group (11 vs. 14 days; p=0.043). Forty (46%) patients receiving olanzapine and forty-one (26%) patients receiving quetiapine were continued on their antipsychotic upon ICU discharge.  
 
Conclusion: This study provides insight into the pharmacological management of ICU agitation and delirium by comparing the use of olanzapine and quetiapine. While olanzapine and quetiapine may have different effects on medication use patterns and mechanical ventilation, both antipsychotics appear similarly effective and well-tolerated in managing ICU-related agitation and delirium. Further research is needed to optimize treatment strategies in order to determine appropriate drug selection and utilization.  
 
Contact email: nina.casanova@emoryhealthcare.org