A Retrospective Analysis of the Effect of Suvorexant on Delirium in the Surgical Intensive Care Unit

Introduction: Sleep optimization is a known factor in prevention and management of delirium. In addition to non-pharmacologic strategies, the 2025 PADIS guideline update recommends melatonin administration for critically ill patients to reduce the prevalence of delirium and improve perceived sleep quality. Suvorexant may also assist with reducing intensive care unit (ICU) delirium in critically ill patients.


Methods: This was a single-center, retrospective analysis of critically ill surgical patients who received ≥2 days of sleep promoting medications with suvorexant (SUV) or without suvorexant (NO-SUV) in the ICU. Patients were excluded if they had an ICU stay < 48 hours or received ECMO. The major outcome was the difference in the proportion of Confusion Assessment Method for the ICU (CAM-ICU) positive days from day of first sleep medication initiation. Notable minor outcomes included ICU length of stay (LOS) and hospital LOS. A regression analysis was performed to assess the effect of suvorexant on proportion of CAM-ICU positive days when accounting for known confounders, such as age, traumatic brain injury (TBI), duration of mechanical ventilation (MV), and APACHE II score.


Results: Overall, 100 patients were included for analysis. The SUV group (n=50) was significantly older (78.0 vs 68.6 years) and had a longer duration of MV (160 vs 21 hours). The max number of sleep-promoting medications received in one day was 3 [2:4] in the SUV group and 1 [1:2] in the NO-SUV group. The median proportion of CAM-ICU positive days was 50.0% [32.1:68.7] in the SUV group and 15.5% [0:60] in the NO-SUV group (p < 0.01). There were no differences in ICU LOS, or hospital LOS. The linear regression analysis showed suvorexant use, increasing age per year, TBI, and increasing duration of MV per hour were independently associated with an increased proportion of CAM-ICU positive days by 15.4% (p=0.04), 0.8% (p=0.02), 35.1% (p=0.01), and 0.04% (p < 0.01), respectively.


Conclusions: This analysis demonstrated an association between suvorexant use and an increase in the proportion of CAM-ICU positive ICU days in surgical ICU patients. However, significant differences in baseline characteristics may have biased the results. Further studies are warranted to further elucidate the effect of suvorexant on delirium in the ICU.