# The Influence of Pharmacological Agents Used During General Anesthesia on the Intensity of Postoperative Pain and the Occurrence of Post-Anesthetic Delirium—A Scoping Review

## TL;DR

This review explores how anesthetic drugs and post-surgery pain affect the risk of delirium after surgery, focusing on agents like dexmedetomidine and remimazolam.

## Contribution

The study provides a scoping review of pharmacological agents' effects on postoperative delirium and pain, highlighting novel agents like dexmedetomidine and remimazolam.

## Key findings

- Dexmedetomidine and remimazolam are associated with reduced postoperative delirium and agitation.
- Hydromorphone provides better pain control than sufentanil, while magnesium sulfate alleviates postoperative symptoms like pain and insomnia.
- Ketamine does not consistently prevent delirium and may increase neuropsychiatric events in some cases.

## Abstract

Introduction: Postoperative delirium, including emergence agitation, is recognized in the post-anesthesia care unit as a fluctuating disturbance of attention and cognition. The current evidence examined suggests that both anesthetic agents and postoperative pain intensity may influence the risk of delirium. The aim of this review is to discuss the significance of pharmacological agents used during anesthesia and the relationship between the intensity of postoperative pain and the occurrence of postoperative delirium in patients undergoing surgical procedures, regardless of age. Methods: A scoping review was conducted from December 2024 to December 2025. The articles identified in each search were limited to those published between 2015 and 2025. Results: Agents such as dexmedetomidine, remimazolam, and magnesium sulfate were examined in the included trials and were reported to be associated with reducing the incidence and severity of postoperative delirium, particularly in pediatric and elderly patients. Analysis of clinical trial outcomes conducted in pediatric populations undergoing various surgical procedures suggests that dexmedetomidine (administered intranasally and intravenously) and alfentanil were associated with lower incidence and severity of emergence delirium compared to standard care or other agents (e.g., midazolam). Higher doses of dexmedetomidine (2 µg/kg) were reported to be associated with improved postoperative analgesia and reduced agitation, without prolonging recovery time or causing serious adverse effects. Propofol, due to its rapid metabolism, was suggested to contribute to shorter emergence times; however, its impact on cognitive function requires further investigation. Additionally, there remains a lack of agreed-upon and/or validated tools and strategies for pain assessment in patients experiencing delirium. Conclusions: The current evidence examined suggests that the use of intranasal dexmedetomidine at appropriate doses may be associated with reduced postoperative pain and agitation without prolonging recovery time or increasing the risk of serious adverse events. Hydromorphone was reported in the included trials to be associated with better postoperative pain control than sufentanil, whereas remimazolam, although associated with reduced delirium incidence in some trials, did not influence the length of stay in the post-anesthesia care unit. Magnesium sulfate, although not significantly affecting the incidence of delirium, was associated with alleviation of postoperative symptoms such as pain and insomnia in adult patients. Ketamine, while commonly used for analgesic therapy, did not demonstrate a consistent association with delirium prevention and, in some studies, was associated with increased neuropsychiatric events. Further research is required to more precisely define optimal perioperative delirium prevention protocols.