Alfaxalone

Alfaxalone
Clinical data
Trade names	Alfaxan
Other names	Alphaxalone; Alphaxolone; Alfaxolone; 3α-Hydroxy-5α-pregnane-11,20-dione; PHAX-001; Phaxan, Alphaxalone (BAN UK)
AHFS/Drugs.com	International Drug Names
License data	US DailyMed: Alfaxan;
Drug class	Neuroactive steroid; General anesthetic;
ATCvet code	QN01AX05 (WHO) ;
Legal status
Legal status	AU: S4 (Prescription only); CA: ℞-only; US: Schedule IV (by veterinarian only);
Pharmacokinetic data
Protein binding	30–50%
Metabolism	Hepatic
Metabolites	Alfaxalone glucuronide (major in dogs); 20-Hydroxyalfaxalone sulfate (major in cats);
Elimination half-life	25 min (dogs); 45 min (cats);
Excretion	Mostly renal
Identifiers
	IUPAC name (3R,5S,8S,9S,10S,13S,14S,17S)-17-acetyl-3-hydroxy-10,13-dimethyl-1,2,3,4,5,6,7,8,9,12,14,15,16,17-tetradecahydrocyclopenta[a]phenanthren-11-one;
CAS Number	23930-19-0 ;
PubChem CID	104845;
IUPHAR/BPS	5461;
DrugBank	DB11371 ;
ChemSpider	94637 ;
UNII	BD07M97B2A;
KEGG	D07282 ;
ChEMBL	ChEMBL190279 ;
CompTox Dashboard (EPA)	DTXSID9022576 ;
ECHA InfoCard	100.164.405
Chemical and physical data
Formula	C21H32O3
Molar mass	332.484 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES O=C2[C@H]3[C@H]([C@@H]1CC[C@H](C(=O)C)[C@@]1(C)C2)CC[C@H]4C[C@H](O)CC[C@]34C;
	InChI InChI=1S/C21H32O3/c1-12(22)16-6-7-17-15-5-4-13-10-14(23)8-9-20(13,2)19(15)18(24)11-21(16,17)3/h13-17,19,23H,4-11H2,1-3H3/t13-,14+,15-,16+,17-,19+,20-,21+/m0/s1 ; Key:DUHUCHOQIDJXAT-OLVMNOGESA-N ;
	(verify)

Alfaxalone, also known as alphaxalone or alphaxolone and sold under the brand name Alfaxan, 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.^[1]^[2]^[3] Though it is more expensive than other induction agents,^[4] it often preferred due to the lack of depressive effects on the cardiovascular system. 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 aren't given, veterinary patients also become agitated and hypersensitive when waking up.

Alfaxalone works as a positive allosteric modulator on GABA_A receptors and, at high concentrations, as a direct agonist of the GABA_A 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.

^ Elks J (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 664–. ISBN 978-1-4757-2085-3.
^ Morton IK, Hall JM (6 December 2012). Concise Dictionary of Pharmacological Agents: Properties and Synonyms. Springer Science & Business Media. p. 11. ISBN 978-94-011-4439-1.
^ "Alfaxalone". Drugs.com.
^ Rezende M (June 2015). "Reintroduced Anesthetic Alfaxalone" (PDF). Clinician's Brief. Archived from the original (PDF) on July 23, 2015. Retrieved July 14, 2017.

[Elks2014-1] Elks J (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 664–. ISBN 978-1-4757-2085-3.

[MortonHall2012-2] Morton IK, Hall JM (6 December 2012). Concise Dictionary of Pharmacological Agents: Properties and Synonyms. Springer Science & Business Media. p. 11. ISBN 978-94-011-4439-1.

[Drugs.com-3] "Alfaxalone". Drugs.com.

[rezende-4] Rezende M (June 2015). "Reintroduced Anesthetic Alfaxalone" (PDF). Clinician's Brief. Archived from the original (PDF) on July 23, 2015. Retrieved July 14, 2017.

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