Mechanism of opioid-induced pupillary effects

  title={Mechanism of opioid-induced pupillary effects},
  author={Merlin D Larson},
  journal={Clinical Neurophysiology},
  • M. Larson
  • Published 1 June 2008
  • Medicine, Biology
  • Clinical Neurophysiology
The effect of ketamine and nitrous oxide on the human pupillary light reflex during general anesthesia
Pupillary Effects of High-dose Opioid Quantified with Infrared Pupillometry
The authors conclude that the pupillary examination and evaluation of the light reflex remain useful for neurologic assessment during opioid toxicity.
Detection of opioid effect with pupillometry
Fentanyl, an agonist at the mu opioid receptor, depresses pupillary unrest
Influence of Depth of Hypnosis on Pupillary Reactivity to a Standardized Tetanic Stimulus in Patients Under Propofol-Remifentanil Target–Controlled Infusion: A Crossover Randomized Pilot Study
In patients receiving a constant infusion of remifentanil at a target concentration of 1 ng/mL, pupillary dilation after a standardized tetanic stimulation was influenced by depth of hypnosis assessed by the bispectral index (BIS).
Suppression of pupillary unrest by general anesthesia and propofol sedation
It is speculated that midbrain nuclei responsible for wakefulness and pupillary unrest are either communicating or share a similar sensitivity to the effects of commonly used anesthetics.
Prediction of the Effect-Site Concentration of Remifentanil Based on the Pupillary Light Reflex Presenting
The aim of this study was to assess the Pupillary Light Reflex (PLR) association with different concentrations of remifentanil, and the possibility of predicting remifENTanil concentrations based on the different parameters of this reflex.
Dynamic assessment of the pupillary reflex in patients on high-dose opioids
Pupillary changes do take place in patients on opioids, however, tolerance to these changes occurs when medication is not increased over time, and dynamic pupillometry can give additional information about the degree of tolerance to opioids.
Pupillary Pain Index Changes After a Standardized Bolus of Alfentanil Under Sevoflurane Anesthesia: First Evaluation of a New Pupillometric Index to Assess the Level of Analgesia During General Anesthesia
The results of this pilot study suggest that PPI score decreases when the level of analgesia increases, and might provide useful information to individually adapt opioid administration before nociceptive stimuli under general anesthesia.
Pupillary unrest, opioid intensity, and the impact of environmental stimulation on respiratory depression
PUAL is a consistent indicator of opioid effect, and distinguishes higher opioid concentrations independently of the stimulating effects of conversational interaction, and shows excellent discrimination in distinguishing higher versus absent-moderate opioid exposure.


Alfentanil Blocks Reflex Pupillary Dilation in Response to Noxious Stimulation But Does Not Diminish the Light Reflex
Dilation of the pupil in response to a noxious stimulus is a measure of opioid effect in isoflurane‐anesthetized volunteers and stimulus‐induced pupillary dilation may be used to evaluate the analgesic component of a combined volatile and opioid anesthetic.
The Effect of Antiemetics on Pupillary Reflex Dilation During Epidural/General Anesthesia
  • M. Larson
  • Medicine
    Anesthesia and analgesia
  • 2003
Patients undergoing lower abdominal surgery under combined epidural/general anesthesia were randomized to receive one of the 5 following open labeled drugs, and metoclopramide produced a small decrease in pupil diameter and transiently depressed reflex dilation, whereas droperidol decreased pupil size at 10 min and depressed Reflex dilation throughout the 40-min study period.
Lidocaine Does Not Depress Reflex Dilation of the Pupil
Latency of pupillary reflex dilation during general anesthesia.
It is concluded that pupillary reflex dilation during anesthesia is not initiated by slowly conducting C fibers and that fentanyl depresses the reflex in a stereotypical manner.
Morphine-induced mydriasis and inhibition of pupillary light reflex and fluctuations in the cat.
It was concluded that morphine disrupts parasympathetic innervation of the iris through interactions with opiate receptors, some of which are in the brain, and this effect has species-characteristic effects on pupillary size.
The Pupillary Light Reflex Effects of Anesthetics and Hyperthermia
Anesthetic-induced inhibition of the pupillary response to light is reversed partially by core hyperthermia, and in contrast to enflurane and isoflurane, 60% N2O has little effect on the pupil.
Pupillary Response to Noxious Stimulation During Isoflurane and Propofol Anesthesia
It is concluded that with these experimental conditions, the pupil is a more sensitive measure of noxious stimulation than the commonly used variables of arterial blood pressure and heart rate.
Neuromuscular blocking drugs do not alter the pupillary light reflex of anesthetized humans.
It is concluded that systemically administered neuromuscular blocking drugs (vecuronium and pancuronium) do not acutely affect the pupillary light reflex in healthy, anesthetized patients.
Sympathetic Nervous System Does Not Mediate Reflex Pupillary Dilation during Desflurane Anesthesia
Pupillary dilation in response to noxious stimulation or desflurane step‐up is not mediated by the sympathetic nervous system (as it is in unanesthetized persons), and inhibition of the pupillo‐constrictor nucleus may be the cause of this dilation.
Autonomic effects of epidural and intravenous fentanyl.
During general anaesthesia, epidural fentanyl enhances antinociception by a spinal mechanism which can be detected by pupillary dilation but not by changes in arterial pressure or heart rate.