Assessment of the effects of intramuscular administration of alfaxalone with and without medetomidine in Horsfield's tortoises (Agrionemys horsfieldii)
Article first published online: 15 MAY 2013
© 2013 The Authors. Veterinary Anaesthesia and Analgesia © 2013 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia
Veterinary Anaesthesia and Analgesia
Volume 40, Issue 6, pages e68–e75, November 2013
How to Cite
Hansen, L. L. and Bertelsen, M. F. (2013), Assessment of the effects of intramuscular administration of alfaxalone with and without medetomidine in Horsfield's tortoises (Agrionemys horsfieldii). Veterinary Anaesthesia and Analgesia, 40: e68–e75. doi: 10.1111/vaa.12045
- Issue published online: 17 OCT 2013
- Article first published online: 15 MAY 2013
- Manuscript Accepted: 12 FEB 2013
- Manuscript Received: 7 AUG 2012
- Agrionemys horsfieldii ;
To characterise four different intramuscular (IM) anaesthetic protocols, two with alfaxalone and two with alfaxalone in combination with medetomidine in terrestrial tortoises.
Blinded, randomized, cross-over experimental study.
Nine healthy adult male Horsfield's tortoises (Agrionemys horsfieldii).
Each tortoise was randomly assigned to one of four different protocols: 1) 10 mg kg−1 alfaxalone; 2) 10 mg kg−1 alfaxalone + 0.10 mg kg−1 medetomidine; 3) 20 mg kg−1 alfaxalone; and 4) 20 mg kg−1 alfaxalone + 0.05 mg kg−1 medetomidine. During the experiment, the following variables were recorded: heart rate; respiratory rate; peripheral nociceptive responses; muscle strength; ability to intubate; palpebral, corneal and tap reflexes; and cloacal temperature.
Protocols 1 and 2 resulted in moderate sedation with no analgesia, and moderate to deep sedation with minimal analgesia, respectively. Protocols 3 and 4 resulted in deep sedation or anaesthesia with variable analgesic effect; these two protocols had the longest total anaesthetic time and allowed intubation in 6/9 and 8/9 tortoises respectively. The total anaesthesia/sedation time produced by alfaxalone was significantly increased (p < 0.05) by the addition of medetomidine. There were no significant differences regarding time to plateau phase and duration of plateau phase. Baseline heart rate of 53 ± 6 beats minute−1 decreased significantly (p < 0.05) with all protocols, and was lower (p < 0.05) in protocols 3 and 4. Heart rate increased after atipamezole administration, but the increase was transient. In two tortoises, extreme bradycardia with no cardiac activity for 10 minutes was observed with protocols 3 and 4.
Conclusion and clinical relevance
Alfaxalone 10 and 20 mg kg−1 IM can be used for sedation for non-painful procedures. Alfaxalone in combination with medetomidine can be used for deeper sedation or anaesthesia, but the observed respiratory and cardiovascular depression may limit its use.