Alfaxalone in Veterinary Practice

What’s Alfaxalone and its function

Alfaxalone (Fig.1) is a neuroactive steroid that has anesthetic properties by acting on the gamma-aminobutyric acid subtype A (GABAA) receptors. It can act as a GABA agonist, when administered in high concentrations or modulate the chloride ion transport across the membrane of neuronal cells when given at low concentrations. Alfaxalone has different mechanisms of action, depending on the dose administered.

Alfaxalone in Veterinary Practice

Fig.1 Chemical Structure of Alfaxalone

This drug is currently being used in veterinary practice as an injectable anesthetic, induction agent or sedative for animals (1).


There is little change in cardiac output or blood pressure, when clinically relevant doses of Alfaxalone are administered to healthy patients (2). Moreover, Alfaxalone has a high therapeutic index, a short duration of action, and is noncumulative (2). Because of these properties, this drug is ideal for use as an induction agent or for providing injectable anesthesia (2).

Furthermore, Alfaxalone can also be administered intramuscularly, facilitating the administration on agitated animals (2).

Side effects

Respiratory depression is the most common side effect: Alfaxalone can lower respiratory rate, minute volume, and blood oxygen saturation and cause apnea (1). Hence, this drug should be administered slowly over a period of at least 60 seconds or until anesthesia is produced, as apnea can occur if given too quickly (1). 

Furthermore, Alfaxalone can lead to depressive effects on the central nervous system such as reduced blood flow to the brain, intracranial pressure, and body temperature (1).

Animals recovering from anesthesia by Alfaxalone, should be taken to a quiet and dark area as they can be very agitated and react poorly to external stimuli such as noise and light (1).


Using our LC-MS, we have analyzed Alfaxalone in feline plasma and estimated the values of LLOQ and ULOQ to be 8 ng/ml and 8000 ng/ml, respectively.

For more information about this analysis contact us by email. 


  1. Wikipedia. Alfaxalone. (Internet) (Updated on 2020 Oct; cited on 2021 Jul) Available from:
  2. Martin J, Kennedy, DVM, Diplomate ACVAA. Alfaxalone for anesthesia in dogs and cats: what you should know. (Internet) Medvets. (Updated 2017 Sept 20; cited on 2021 Oct 15th) Available from:

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