Increasing plasma ketamine concentrations decrease the minimum alveolar concentration of isoflurane in rabbits
Linda S Barter1, Bruno H Pypendop1
1Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States.
Frontiers in Veterinary Science
|July 4, 2025
Summary
Increasing ketamine concentration reduces isoflurane minimum alveolar concentration (MAC) in rabbits. Ketamine doses between 1-4 µg/mL may offer benefits with few side effects.
Area of Science:
- Veterinary Anesthesiology
- Pharmacology
Background:
- Isoflurane is a common anesthetic agent.
- Ketamine is an anesthetic with analgesic properties.
- Understanding drug interactions is crucial for safe anesthesia.
Purpose of the Study:
- To investigate the effect of increasing plasma ketamine concentrations on isoflurane MAC in rabbits.
- To determine a dose-response relationship between ketamine and isoflurane MAC.
Main Methods:
- Six New Zealand white rabbits were anesthetized with isoflurane.
- Intravenous ketamine was administered to achieve target plasma concentrations (0.5-12 µg/mL).
- Isoflurane MAC, vital signs, and plasma ketamine levels were measured.
Main Results:
- Ketamine significantly reduced isoflurane MAC starting at 1 µg/mL.
- Heart rate decreased at ketamine concentrations of 2 µg/mL and higher.
- Adverse effects like muscle tone increase and movement were noted at higher ketamine doses.
Conclusions:
- Increasing ketamine concentrations decrease isoflurane MAC in rabbits.
- Ketamine concentrations of 1-4 µg/mL may provide anesthetic benefits with minimal adverse effects.
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