Alfaxalone

Alfaxalone, also known as alphaxalone or alphaxolone and sold under the brand name Alfaxan and Faxone, is a neuroactive steroid and general anesthetic which is used currently in veterinary practice as an induction agent for anesthesia and as an injectable anesthetic. The most common side effect seen in current veterinary practice is respiratory depression when Alfaxan is administered concurrently with other sedative and anesthetic drugs; when premedications are not given, veterinary patients also become agitated and hypersensitive when waking up.

Alfaxalone works as a positive allosteric modulator on GABAA receptors and, at high concentrations, as a direct agonist of the GABAA receptor. It is cleared quickly by the liver, giving it a relatively short terminal half-life and preventing it from accumulating in the body, lowering the chance of overdose.

Veterinary use

Alfaxalone is used as an induction agent, an injectable anesthetic, and a sedative in animals. While it is commonly used in cats and dogs, it has also been successfully used in rabbits, horses, sheep, pigs, and exotics such as red-eared turtles, axolotl, green iguanas, marmosets, and koi fish. As an induction agent, alfaxalone causes the animal to relax enough to be intubated, which then allows the administration of inhalational anesthesia. Premedication (administering sedative drugs prior to induction) reduces the required induction dose of alfaxalone. Alfaxalone can be used for total intravenous anesthesia; this is especially useful in airway procedures such as bronchoscopy to avoid exposing the clinician to volatile anesthetic. Once the administration of alfaxalone stops, the animal quickly recovers from anesthesia.