Related Experiment Video
Updated: Jun 22, 2026
Evaluation of Respiratory System Mechanics in Mice using the Forced Oscillation Technique
Published on: May 15, 2013
Effect of exposure to fentanyl aerosol in mice on breathing pattern and respiratory variables
Laxmi Manral1, Natrajan Muniappan, Pradeep K Gupta
1Synthetic Chemistry Division, Defence Research and Development Establishment (DRDE), Gwalior, India. luxmimanral@yahoo.com
Abstract:
The breathing pattern of mice that were exposed to fentanyl aerosol was studied (2.7, 5.7, 6.0, 10.0, and 23.6 microg/m(3); for 1 hour), using dimethyl sulfoxide as a vehicle. This study was conducted in a head-only exposure assembly. Body plethysmographs connected to a volumetric pressure transducer were used to capture the respiratory signals, and an on-line computer program capable of recognizing the changes in the breathing pattern was used for monitoring the respiratory pattern. The response of mice to fentanyl exposure was found to be concentration dependent. A lower concentration (2.7 microg/m(3)) showed fast recovery and no mortality, while 100% mortality was observed at a higher concentration (23.6 microg/m(3)). No sensory, pulmonary irritation, and airway limitation in mice was observed, and death occurred probably due to respiratory depression. The concentration that decreased 50% of the respiratory frequency (RD(50)) was estimated to be 6.4 microg/m(3). The extrapolated human threshold limit value, calculated from the RD(50) value, was found to be 0.192 microg/m(3). The concentration that caused 50% mortality in exposed mice (LC(50)) was estimated to be 8.8 microg/m(3). This study shows that aerosolized fentanyl does not cause sensory and pulmonary irritation, and since the RD(50) and LC(50) are very close with a low safety margin, this type of sedative should not be used as an incapacitating agent.
Insights
Aerosolized fentanyl exposure in mice demonstrated a concentration-dependent effect on breathing patterns, leading to respiratory depression and high mortality at elevated concentrations. The study advises against using fentanyl as an incapacitating agent due to its narrow safety margin.
Area of Science:
- Toxicology
- Pharmacology
- Respiratory Physiology
Background:
- Fentanyl is a potent synthetic opioid with significant physiological effects.
- Understanding the respiratory impact of aerosolized fentanyl is crucial for safety assessments.
Purpose of the Study:
- To investigate the effects of varying concentrations of aerosolized fentanyl on the breathing patterns of mice.
- To determine the concentration-response relationship and identify key toxicological endpoints.
Main Methods:
- Mice were exposed to different concentrations of fentanyl aerosol (2.7-23.6 microg/m(3)) for one hour in a head-only system.
- Respiratory signals were monitored using body plethysmography and a volumetric pressure transducer.
- An on-line computer program analyzed changes in breathing patterns to assess fentanyl's effects.
Main Results:
- Fentanyl exposure caused a concentration-dependent decrease in respiratory frequency, with 100% mortality at 23.6 microg/m(3).
- The concentration causing 50% reduction in respiratory frequency (RD(50)) was 6.4 microg/m(3), and the concentration causing 50% mortality (LC(50)) was 8.8 microg/m(3).
- No sensory, pulmonary irritation, or airway limitation was observed; death was attributed to respiratory depression.
Conclusions:
- Aerosolized fentanyl poses a significant risk of respiratory depression and mortality.
- The close proximity of RD(50) and LC(50) values indicates a low safety margin.
- Fentanyl should not be considered for use as an incapacitating agent due to its high toxicity profile.
