Evaluation of the Efficacy and Safety of Quetiapine in the Treatment of Delirium in Adult ICU Patients: A Retrospective Comparative Study

Background: Quetiapine is commonly prescribed off-label to manage delirium in intensive care unit (ICU) patients. However, limited studies comparing its efficacy and safety to those of other antipsychotics exist in the literature. Method: A retrospective, single-center chart review study was conducted on adults admitted to the ICU between January 2017 and August 2022, who were diagnosed with delirium and treated with a single antipsychotic and had no neurological medical conditions, active alcohol withdrawal, or prior use of antipsychotics. Data were analyzed using SPSS software version 28, with p-values of <0.05 indicating statistical significance. Results: In total, 47 patients were included, of whom 22 (46.8%), 19 (40.4%), 4 (8.5%), and 2 (4.3%) were on quetiapine, haloperidol, risperidone, and olanzapine, respectively. The median number of hours needed to resolve delirium were 12 (21.5), 23 (28), 13 (13.75), and 36 (10) (p = 0.115) for quetiapine, haloperidol, risperidone, and olanzapine, respectively, with haloperidol being used for a significantly shorter median number of days than quetiapine (3 (2.5) days vs. 7.5 (11.5) days; p = 0.007). Of the medication groups, only quetiapine-treated patients received a significantly higher median maintenance compared to the initiation dose (50 (50) mg vs. 50 (43.75) mg; p = 0.039). For the length of stay in the ICU and hospital, delirium-free days, % of ICU time spent in delirium, ventilator-free days, the difference between the highest and baseline QTc intervals, and ICU and hospital mortalities, no significant difference was observed between the groups. Conclusions: Overall, the use of quetiapine in our retrospective study seems to not be advantageous over the other drugs in terms of efficacy and safety outcomes.