Exotis ISSN 2398-2985

Reptiles

Alfaxalone

Synonym(s): Alfaxan, Alfaxolone, Alphaxalone, Alphaxolone

Contributor(s): Vetstream Ltd, David Perpinan

Introduction

Name

  • Alfaxalone.

Class of drug

  • Neuroactive steroid general anesthetic.
  • Agonist of GABA receptors.

Description

Chemical name

  • 3-alpha- hydroxy-5-alpha-pregnane-11,20-dione.

Molecular formula

  • C21H32O3.

Molecular weight

  • 332.48.

Physical properties

  • Clear, slightly viscous solution.

Storage requirements

  • Store below 25°C/77°F.
  • Do not freeze. Some sources recommend not to refrigerate, but other sources do not.
  • Protect from light.
  • Do not store opened vials (no antibacterial agent included). However, open vials are commonly used over weeks with no noticeable adverse effects and with apparent full efficacy. Aseptic technique and (maybe) refrigeration help prolonging the shelf-life of vials.

Uses

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Indications

  • Immobilization, sedation and anesthesia in reptiles Anesthesia overview.
  • Commonly used as an induction agent to facilitate intubation for inhalant anesthesia Gaseous anesthesia.
  • Intravenous use is recommended over intramuscular administration.
  • Alfaxalone can be combined with other pre-anesthetic and anesthetic drugs.
  • It can be used for long anesthetic events, either as constant rate infusion (CRI) or using multiple injections. While it is better for this purpose than propofol and adverse effects do not seem to increase associated with repeated or prolonged use, it is better used for short procedures or for induction followed by maintenance with isoflurane or sevoflurane.
  • Due to the pH of alfaxalone (6.5-7), IM injection may be less painful than when ketamine (pH 3.5-5.5) is used.

Administration

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Pharmacokinetics

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Precautions

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Adverse Reactions

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Knotek Z (2017) Induction to inhalation anaesthesia in agamid lizards with alfaxalone. Veterinarni Medicina 62 (1), 41-43 VetMedResource.
  • West J A (2017) Alfaxalone. J Exotic Pet Med 26 (2), 156-161 JExoticPetMed.
  • Knotek Z (2014) Alfaxalone as an induction agent for anesthesia in terrapins and tortoises. Vet Rec 175 (13), 372 PubMed.
  • Hansen L L & Bertelsen M F (2013) Assessment of the effects of intramuscular administration of alfaxalone with and without medetomidine in Horsfield’s tortoises (Agrionemys horsfieldii). Vet Anaesth Analg 40 (6), e68-75 PubMed.
  • Knotek Z, Hrda A, Knotkova Z et al (2013) Alfaxalone anaesthesia in the green iguana (Iguana iguana). Acta Veterinaria Brno 82 (1), 109-114 PubMed.
  • Olsson A, Phalen D & Dart C (2013) Preliminary studies of alfaxalone for intravenous immobilization of juvenile captive estuarine crocodiles (Crocodylus porosus) and Australian freshwater crocodiles (Crocodylus johnstoni) at optimal and selected sub-optimal thermal zones. Vet Anaesth Analg 40 (5), 494-502 PubMed.
  • Shepard M K, Divers S, Braun C et al (2013) Pharmacodynamics of alfaxalone after single-dose intramuscular administration in red-eared sliders (Trachemys scripta elegans): a comparison of two different doses at two different ambient temperatures. Vet Anaesth Analg 40 (6), 590-598 PubMed.

Other sources of information

  • Meredith A (2015) Ed Small Animal Formulary. Part B: Exotic Pets. 9th edn. BSAVA, UK.
  • Veterinary Medicines Directorate (2013) Veterinary Medicines Guidance Notes. Website: www.gov.uk.

Organisation(s)

  • National Office of Animal Health (NOAH) Compendium of Data Sheets for Animal Medicines. Website: www.noahcompendium.co.uk.

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