Preanesthetic Opioids and Subjective Effects Before Induction
Giving a small opioid before induction is still common in many rooms—part habit, part hope that patients will feel calmer on the way into the OR. A September 2026 open-access randomized trial in Cell Reports Medicine put that habit under a finer lens: what do elective surgical patients actually report feeling minutes after intravenous morphine, oxycodone, or fentanyl?
About 199 ASA I–II adults received a standardized multimodal preoperative medication, then were randomized to morphine 10 mg, oxycodone 5 mg, or fentanyl 0.1 mg IV. They rated effects on 0–10 scales immediately before and three minutes after the opioid. The dominant findings were not comfort: intoxication, sedation, and dizziness led the list. Nearly everyone (about 96%) reported feeling intoxicated. Only about 23% said they felt better overall. Desirable effects such as less anxiety or more relaxation were modest. Fentanyl tended to score highest for intoxication, sedation, dizziness, and euphoria; morphine was lower; oxycodone usually sat in between. Interindividual scatter was large in every arm.
How I read this as a clinician
This trial does not prove that pre-induction opioids never help a specific patient. It does challenge the casual assumption that a “little fentanyl now” reliably improves the preoperative experience. If most patients feel intoxicated and few feel better, the default justification for routine pre-anesthetic opioids looks thinner—especially when multimodal anxiolysis, clear communication, and non-opioid adjuncts are already on the table.
I also notice what the study is not. It is not a trial of intraoperative analgesia, emergence, or postoperative opioid requirements. It speaks to the minutes before induction. That is still a clinically meaningful window: it shapes how we talk with patients, how we document informed comfort measures, and how we avoid stacking early opioid effects onto induction hemodynamics without a clear benefit.
Clinical takeaways
- In this RCT, pre-induction morphine, oxycodone, and fentanyl produced mainly undesirable subjective effects (intoxication, sedation, dizziness), with only modest desirable effects.
- Almost all patients reported intoxication; only about one in four reported feeling better.
- Fentanyl’s subjective intensity was generally higher than morphine’s in this dosing comparison; oxycodone was intermediate.
- Large person-to-person variability argues against a one-size-fits-all “always give a premed opioid” habit.
- Consider reserving pre-induction opioids for a clear indication, and lean on non-opioid strategies when the goal is anxiolysis or comfort rather than analgesia for painful stimuli.
Source
- Intoxication and other subjective effects of preanesthetic opioids in surgical patients: A randomized controlled trial. Cell Reports Medicine. Published online September 11, 2026 (EudraCT: 2020-004920-40). Full text
This post is clinician commentary for educational discussion. It is not medical advice for any reader’s personal care. Anesthesia and perioperative decisions should be made with the treating clinician based on the individual patient’s circumstances.