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Updated: Aug 4, 2025
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Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
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Morphine and Hydromorphone Effects, Side Effects, and Variability: A Crossover Study in Human Volunteers
Konrad Meissner1, Albert Dahan2, Erik Olofsen2
1Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany; Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands; Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri.
Anesthesiology
|April 4, 2023
Summary
Hydromorphone offers better analgesia relative to respiratory depression compared to morphine, with a later onset of effects and longer duration of respiratory depression for morphine. This suggests hydromorphone may be a superior clinical choice.
Area of Science:
- Pharmacology and Toxicology
- Anesthesiology and Pain Management
- Clinical Research
Background:
- Opioid analgesia and respiratory depression balance is a clinical challenge in acute care settings.
- Morphine and hydromorphone are standard postoperative analgesics, but their comparative effects are poorly understood.
- This study investigated the differences in onset, magnitude, duration, and variability of analgesic and ventilatory effects between IV morphine and hydromorphone.
Purpose of the Study:
- To test the hypothesis that IV morphine and hydromorphone exhibit distinct profiles in their analgesic and ventilatory effects.
- To compare the onset, magnitude, duration, and variability of clinical effects between morphine and hydromorphone.
- To provide data for more rational opioid selection in clinical practice.
Main Methods:
- A randomized crossover study was conducted in 42 healthy volunteers.
- Subjects received a 2-hour intravenous infusion of hydromorphone (0.05 mg/kg) or morphine (0.2 mg/kg) 1-2 weeks apart.
- Measurements included arterial opioid concentrations, analgesia (heat pain tolerance, verbal analog pain scores), miosis (pupil diameter), end-expired carbon dioxide, and respiratory rate for 12 hours post-infusion.
Main Results:
- Morphine showed less analgesia and a less favorable analgesia-to-respiratory depression ratio compared to hydromorphone.
- The onset of miosis and respiratory depression was later for morphine, while its respiratory depression duration was longer.
- Interindividual variability in clinical effects did not differ significantly between the two opioids.
Conclusions:
- Hydromorphone may possess a superior clinical profile compared to morphine, offering better analgesia relative to respiratory depression.
- The timing of various clinical effects (analgesia, miosis, respiratory depression) was not coincident for either opioid.
- Findings support more informed opioid selection, potentially favoring hydromorphone in certain clinical scenarios.
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