Related Experiment Video

Updated: Aug 29, 2026

Application of Dixon's Up-and-Down Design to Estimate the Minimum Alveolar Concentration of Sevoflurane in Rats with Refined Movement Classification
03:02

Application of Dixon's Up-and-Down Design to Estimate the Minimum Alveolar Concentration of Sevoflurane in Rats with Refined Movement Classification

Published on: July 25, 2025

Meloxicam, a specific COX-2 inhibitor, does not enhance the isoflurane minimum alveolar concentration reduction

Martín Santos1, Viviana Kunkar, Palma García-Iturralde

  • 1From the Servicio de Cirugía Experimental, Hospital Universitario Puerta de Hierro, Madrid, Spain.

Anesthesia and Analgesia
|January 27, 2004
PubMed
Abstract

Insights

Aspirin, but not meloxicam, synergistically enhances morphine's effect in reducing isoflurane minimum alveolar concentration (MAC(ISO)) in rats. This finding highlights differential interactions between opioids and cyclooxygenase inhibitors.

Area of Science:

  • Anesthesiology
  • Pharmacology
  • Pain Management

Background:

  • Nonselective cyclooxygenase (COX) inhibitors show a synergistic effect with morphine on isoflurane minimum alveolar concentration (MAC(ISO)) in rats.
  • The influence of specific COX-2 inhibitors on this interaction requires further investigation.

Purpose of the Study:

  • To investigate the effect of specific COX-2 inhibitors, meloxicam, on the morphine-induced decrease in isoflurane MAC(ISO) in rats.
  • To compare the synergistic effects of aspirin and meloxicam when co-administered with morphine.

Main Methods:

  • Sixty-four female rats were anesthetized with isoflurane.
  • Animals were grouped to receive saline, aspirin, morphine, morphine + aspirin, meloxicam, or morphine + meloxicam.
  • Minimum alveolar concentration of isoflurane (MAC(ISO)) was determined via tail clamp stimulus.

Main Results:

  • Morphine administration significantly reduced MAC(ISO).
  • Co-administration of morphine with meloxicam (1 and 3 mg/kg) did not potentiate this reduction.
  • Morphine combined with aspirin demonstrated the greatest reduction in MAC(ISO), indicating a synergistic effect.

Conclusions:

  • A synergistic effect exists between morphine and aspirin in reducing rat isoflurane MAC(ISO).
  • This synergistic effect was not observed between morphine and the COX-2 inhibitor meloxicam.

More Related Videos

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities07:23

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities

Published on: July 29, 2014

Related Concept Videos

Opioid Analgesics: Morphine and Other Natural Cogeners01:20

Opioid Analgesics: Morphine and Other Natural Cogeners

Opioids are a class of drugs that mimic endogenous opioid peptides and act on opioid receptors, and help in pain relief. These compounds are classified as natural, synthetic, or semi-synthetic. Natural opioids, like morphine, codeine, and thebaine, are derived from the opium poppy plant (Papaver somniferum or Papaver album) and are termed opiates. Synthetic opioids are artificial, while semi-synthetic opioids combine natural and synthetic compounds. Morphine, a prototypical opioid, possesses a...
Inhalational Anesthetics: Overview01:20

Inhalational Anesthetics: Overview

Inhalation anesthetics are drugs that induce general anesthesia upon inhalation. They work by increasing the sensitivity of GABAA receptors or inhibiting NMDA receptors, leading to a decrease in central nervous system activity. The depth of anesthesia can be rapidly adjusted by changing the concentration of the inhaled gas. Some common examples of inhalational anesthetics include volatile liquids like isoflurane, desflurane, sevoflurane and gases like xenon and nitrous oxide. Isoflurane, a...
Analgesia and Pain Management01:25

Analgesia and Pain Management

Pain is critical to various clinical pathologies, provoking an urgent need for effective management. Pain, whether acute or chronic, is a complex neurochemical process. Its alleviation depends on the type, with nonopioid analgesics effective for mild to moderate pain, such as musculoskeletal or inflammatory pain, while neuropathic pain responds best to anticonvulsants, tricyclic antidepressants, or serotonin/norepinephrine reuptake inhibitors. For severe acute or chronic pain, opioids may be...
Parenteral Anesthetics: Overview01:24

Parenteral Anesthetics: Overview

Intravenous anesthetics are drugs administered parenterally to induce anesthesia or sedation. Propofol is a widely used agent formulated as a 1% emulsion in soybean oil, glycerol, and egg phosphatide. It induces rapid anesthesia primarily due to its rapid distribution from the bloodstream to target tissues and is metabolized in the liver. However, it can cause significant pain on injection and hypertriglyceridemia. Fospropofol, a water-based prodrug of propofol, lacks these adverse effects.