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Postanaesthetic effects of ketamine–midazolam and ketamine–medetomidine on gastrointestinal transit time in rabbits anaesthetised with isoflurane
  1. Julie Botman1,2,
  2. Fanny Hontoir1,
  3. Pascal Gustin2,
  4. Carole Cambier2,
  5. Fabien Gabriel1,
  6. Alex Dugdale3 and
  7. Jean-Michel Vandeweerd
  1. 1 Integrated Veterinary Research Unit, Namur Research Institute for Life Science, Department of Veterinary Medicine, University of Namur, Namur, Belgium
  2. 2 Department of Pharmacology, Pharmacotherapy and Toxicology, University of Liege Faculty of Veterinary Medicine, Liege, Belgium
  3. 3 Chester Gates Veterinary Specialists, Chester, UK
  1. Correspondence to Dr Jean-Michel Vandeweerd; jean-michel.vandeweerd{at}


Background Gastrointestinal stasis is a common perianaesthetic complication in rabbits. The objective of this study was to assess the impact on gastrointestinal transit time of ketamine–midazolam (KMZ) versus ketamine–medetomidine (later antagonised by atipamezole) (KMT-A) in rabbits anaesthetised with isoflurane.

Methods This was a cross-over, randomised, single-blinded, controlled, experimental trial. Seven healthy adult New Zealand White rabbits were used. Gastrointestinal transit time was assessed by contrast radiography in awake rabbits. Presence of contrast medium in the small intestine (gastric transit time), in the caecum (small intestinal transit time) and in faeces in the colon was assessed. One week later, 55 minutes isoflurane anaesthesia was induced with ketamine (15 mg/kg) and either midazolam (3 mg/kg) or medetomidine (0.25 mg/kg) by intramuscular injection. Thirty minutes after discontinuation of isoflurane, atipamezole (0.5 mg/kg) was administered only to rabbits in KMT-A treatment. Gastrointestinal transit time was then assessed in both treatment groups, beginning 30 minutes after cessation of isoflurane administration. Two weeks later, the treatment groups were interchanged.

Results Gastric and small intestinal transit times were significantly longer with KMT-A (92±109 minutes and 214±119 minutes, respectively) than with KMZ (1±0 minutes and 103±6 minutes, respectively) and in the awake state (7±7 minutes and 94±32 minutes, respectively).

Conclusion Clinicians should therefore be aware of the potential gastrointestinal side effects of KMT-A, particularly in rabbits at risk for gastrointestinal stasis.

  • anaesthesia
  • rabbits
  • gastrointestinal
  • midazolam
  • medetomidine
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  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The ethical committee for animal welfare of Namur approved the experimental protocol (17288 VA).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article.

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