2026 Eastern States Conference

Authors:
Cassidy Cox1, PharmD, Deepika Sivakumar1,2, PharmD, MS, Patricia Hernández2, MD, Bryan Hayes, PharmD1,2, Marianna Hernandez1, PharmD Candidate 
1Department of Pharmacy, Massachusetts General Hospital, Boston, MA 
2Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA 
 
Background:
Ketamine is used for procedural sedation in the emergency department (ED) for its analgesic and dissociative properties. It remains unclear whether substance use disorder (SUD) is associated with higher ketamine doses during procedural sedation. 
Objective: To evaluate if ketamine doses for procedural sedation differed between patients with and without various SUD. 

Learning Objective:  
Evaluate the impact of substance use disorder on dosing of ketamine for procedural sedation in the emergency department. 

Methods:  
This was a single-center, retrospective cohort study of patients receiving ketamine for procedural sedation in the ED from March 2018 to May 2025. Patients with SUD were identified using ICD-10 codes and matched 1:1 by age and weight using coarsened exact matching. SUD types included use of alcohol, opioids, cannabis, sedatives, cocaine or other stimulants, hallucinogens, nicotine, inhalants, or other psychoactive substances. The primary outcome was time-averaged ketamine dose as the cumulative dose in mg divided by sedation duration in minutes. Secondary outcomes included weight-based time-averaged ketamine dose as dose in mcg divided by weight in kg divided by documented sedation duration in minutes, and administration of additional sedative agents such as propofol and midazolam. The Student’s t-test was used for continuous data for analysis of means, the Mann-Whitney U test was used for continuous data for analysis of medians, and the Chi-squared test was used for categorical data. 

Results:  
92 patients were included in analysis, with 44 in the SUD group and 48 in the non-SUD group. Time-averaged ketamine dose (mg/min) did not significantly differ between the SUD group and non-SUD group (2.17 versus 3.09; p=0.062). Weight-based, time averaged ketamine dose (mcg/kg/min) also did not significantly differ between groups (29.5 versus 40.5; p-value 0.059). A total of 63 patients (68%) received additional sedatives, with no significant difference between SUD and non-SUD groups (72.7% versus 60.4%; p-value=0.212). There was no significant difference in propofol use (66% vs 46% in SUD and non-SUD groups, respectively; p=0.056). However, a higher mean propofol doses in mcg/kg/min were used in the SUD group (48.2 versus 22.7; p=0.009). 

Conclusion and Relevance:  
Patients with SUD did not require higher doses of ketamine for procedural sedation in the ED. Patients with SUD were also not more likely to require additional sedatives but did receive higher doses of propofol when administered in addition to ketamine. While not significant, patients with SUD were sedated almost 15 minutes longer than patients without SUD, possibly due to higher doses of concomitant propofol. Future studies should evaluate dosing by SUD type and sedation-related adverse events.