ALFAXALONE

Details

Stereochemistry	ABSOLUTE
Molecular Formula	C21H32O3
Molecular Weight	332.477
Optical Activity	UNSPECIFIED
Defined Stereocenters	8 / 8
E/Z Centers	0
Charge	0

SHOW SMILES / InChI

Structure Search

SMILES

CC(=O)[C@H]1CC[C@H]2[C@@H]3CC[C@H]4C[C@H](O)CC[C@]4(C)[C@H]3C(=O)C[C@]12C

InChI

InChIKey=DUHUCHOQIDJXAT-OLVMNOGESA-N

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

HIDE SMILES / InChI

Molecular Formula	C21H32O3
Molecular Weight	332.477
Charge	0
Count

Stereochemistry	ABSOLUTE
Additional Stereochemistry	No
Defined Stereocenters	8 / 8
E/Z Centers	0
Optical Activity	UNSPECIFIED

Description
Sources: http://www.alfaxan.co.uk/what-is-alfaxan
Curator's Comment: description was created based on several sources, including: http://www.vasg.org/pdfs/alfaxalone_vasg_05_11.pdf | https://www.fda.gov/downloads/AnimalVeterinary/Products/ApprovedAnimalDrugProducts/FOIADrugSummaries/UCM326904.pdf

Alfaxalone is a rapidly acting hydrophobic synthetic neurosteroid. It is indicated for the induction and maintenance of anesthesia and for induction of anesthesia followed by maintenance with an inhalant anesthetic, in cats and dogs. Alfaxalone induces anaesthesia through activity at the gamma amino butyric acid sub-type A receptor (GABAA) present on cells in the Central Nervous System (CNS). Alfaxalone enhances the effects of GABA at the GABAA receptors resulting in opening of channels into the cells and an influx of chloride ions. This causes hyperpolarisation of the cells and inhibition of neural impulse transmission. Alfaxalone can be safely combined with premedicants (xylazine, (dex)medetomidine, acepromazine, midazolam), opioids (morphine, methadone, hydromorphone, butorphanol, nalbuphine, buprenorphine, fentanyl), and NSAIDs. Alfaxalone’s adverse reactions are: hypotension, tachycardia, apnea, hypertension, bradypnea and others.

CNS Activity

Originator

Approval Year

Targets

Primary Target	Pharmacology	Condition	Potency
Sodium channel protein type II alpha subunit 27 Target ID: CHEMBL4187 Sources: https://www.ncbi.nlm.nih.gov/pubmed/22538831	Blocker 555
Sodium channel protein type IV alpha subunit 23 Target ID: CHEMBL2072 Sources: https://www.ncbi.nlm.nih.gov/pubmed/22538831	Blocker 555
GABAA receptor (Bovine) 1 Target ID: GABAA receptor (Bovine) Sources: https://www.ncbi.nlm.nih.gov/pubmed/3032320	Agonist 2752

Conditions

Condition	Modality	Targets	Highest Phase	Product
Pain 619 Sources: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f5d57f72-71e4-46af-b262-673ceabeff04	Primary		Approved 8583	Alfaxan Approved Use ALFAXAN is indicated for the induction and maintenance of anesthesia and for induction of anesthesia followed by maintenance with an inhalant anesthetic, in cats and dogs. Launch Date 2012

C_max

Value	Dose	Co-administered	Analyte	Population
5.57 μg/mL EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/31124836/	0.5 mg/kg single, intravenous dose: 0.5 mg/kg route of administration: Intravenous experiment type: SINGLE co-administered:		ALFAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: MALE food status: UNKNOWN

T_1/2

Value	Dose	Co-administered	Analyte	Population
8 min EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/31124836/	0.5 mg/kg single, intravenous dose: 0.5 mg/kg route of administration: Intravenous experiment type: SINGLE co-administered:		ALFAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: MALE food status: UNKNOWN

Doses

Dose	Population	Adverse events
0.55 mg/kg single, intravenous Highest studied dose Dose: 0.55 mg/kg Route: intravenous Route: single Dose: 0.55 mg/kg Sources: https://pubmed.ncbi.nlm.nih.gov/31124836/	healthy, ADULT Health Status: healthy Age Group: ADULT Sex: M Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/31124836/	Sources: https://pubmed.ncbi.nlm.nih.gov/31124836/
0.0225 mg single, intravenous Studied dose Dose: 0.0225 mg Route: intravenous Route: single Dose: 0.0225 mg Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/	healthy, ADULT Health Status: healthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/	Disc. AE: Cyanosis, Wheeze... Other AEs: Cough, Salivation... AEs leading to discontinuation/dose reduction: Cyanosis Wheeze Tachycardia Other AEs: Cough Salivation Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/
16.4 ug/kg/min single, intravenous Studied dose Dose: 16.4 ug/kg/min Route: intravenous Route: single Dose: 16.4 ug/kg/min Sources: https://pubmed.ncbi.nlm.nih.gov/6536519/	healthy, ADULT Health Status: healthy Age Group: ADULT Sex: unknown Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/6536519/	Sources: https://pubmed.ncbi.nlm.nih.gov/6536519/
21 ug/kg/min single, intravenous Studied dose Dose: 21 ug/kg/min Route: intravenous Route: single Dose: 21 ug/kg/min Sources: https://pubmed.ncbi.nlm.nih.gov/6536519/	healthy, ADULT Health Status: healthy Age Group: ADULT Sex: unknown Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/6536519/	Sources: https://pubmed.ncbi.nlm.nih.gov/6536519/

AEs

AE	Significance	Dose	Population
Cough		0.0225 mg single, intravenous Studied dose Dose: 0.0225 mg Route: intravenous Route: single Dose: 0.0225 mg Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/	healthy, ADULT Health Status: healthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/
Salivation		0.0225 mg single, intravenous Studied dose Dose: 0.0225 mg Route: intravenous Route: single Dose: 0.0225 mg Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/	healthy, ADULT Health Status: healthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/
Cyanosis	Disc. AE	0.0225 mg single, intravenous Studied dose Dose: 0.0225 mg Route: intravenous Route: single Dose: 0.0225 mg Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/	healthy, ADULT Health Status: healthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/
Tachycardia	Disc. AE	0.0225 mg single, intravenous Studied dose Dose: 0.0225 mg Route: intravenous Route: single Dose: 0.0225 mg Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/	healthy, ADULT Health Status: healthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/
Wheeze	Disc. AE	0.0225 mg single, intravenous Studied dose Dose: 0.0225 mg Route: intravenous Route: single Dose: 0.0225 mg Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/	healthy, ADULT Health Status: healthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/6830684/

PubMed

Title	Date	PubMed
Systemic central venous oxygen saturation is associated with clot strength during traumatic hemorrhagic shock: A preclinical observational model.	2010-12-07	21138566
Induction of anaesthesia with alfaxalone or propofol before isoflurane maintenance in cats.	2010-07-17	20643885
Effect of propofol and alfaxalone on pain after ovariohysterectomy in cats.	2010-03-13	20228368
Alfaxalone induction dose following administration of medetomidine and butorphanol in the dog.	2010-01	20017814
Retinal afferents synapse with relay cells targeting the middle temporal area in the pulvinar and lateral geniculate nuclei.	2010	20179789
Role of neurosteroids in regulating cell death and proliferation in the late gestation fetal brain.	2009-10-20	19591903
Plasma pharmacokinetics of alfaxalone in both premedicated and unpremedicated Greyhound dogs after single, intravenous administration of Alfaxan at a clinical dose.	2009-10	19754921
Effects of gamma-aminobutyric acid (GABA) agonists and a GABA uptake inhibitor on pharmacoresistant seizure like events in organotypic hippocampal slice cultures.	2009-10	19535226
Alfaxalone in cyclodextrin for induction and maintenance of anaesthesia in ponies undergoing field castration.	2009-09	19709052
Use of alfaxalone in rabbits.	2009-02-07	19202182
Induction of anaesthesia in wild rabbits using a new alfaxalone formulation.	2009-01-24	19168884
The cardiorespiratory and anesthetic effects of clinical and supraclinical doses of alfaxalone in cats.	2009-01	19121158
The pharmacokinetics and pharmacodynamics of alfaxalone in cats after single and multiple intravenous administration of Alfaxan at clinical and supraclinical doses.	2008-12	19000281
Cardiorespiratory and anesthetic effects of clinical and supraclinical doses of alfaxalone in dogs.	2008-11	18793290
Clinical evaluation of alfaxalone in cyclodextrin for the induction of anaesthesia in rabbits.	2008-09-27	18820329
Anaesthesia for the geriatric dog and cat.	2008-06-01	21851715
A comparison of microbial growth in alfaxalone, propofol and thiopental.	2008-04	18194193
Changes in relative potency among positive GABA(A) receptor modulators upon discontinuation of chronic benzodiazepine treatment in rhesus monkeys.	2007-05	17245585
In silico prediction of pregnane X receptor activators by machine learning approaches.	2007-01	17003167
Plasma pharmacokinetics of alfaxalone in dogs after an intravenous bolus of Alfaxan-CD RTU.	2006-07	16764587
Quantification of collagen and proteoglycan deposition in a murine model of airway remodelling.	2005-04-08	15819978
A single M1 residue in the beta2 subunit alters channel gating of GABAA receptor in anesthetic modulation and direct activation.	2003-10-31	12939268
Pharmacological characterization of the homomeric and heteromeric UNC-49 GABA receptors in C. elegans.	2003-03	12642390
Mutation of the GABAA receptor M1 transmembrane proline increases GABA affinity and reduces barbiturate enhancement.	2002-03	11955521
Influence of membrane cholesterol on modulation of the GABA(A) receptor by neuroactive steroids and other potentiators.	2001-11	11704651
Identification of a human nuclear receptor defines a new signaling pathway for CYP3A induction.	1998-10-13	9770465
Selective cyclodextrin inhibition of alfaxolone-induced ataxia.	1996-05	8799881
GABAA receptor subtypes: ligand binding heterogeneity demonstrated by photoaffinity labeling and autoradiography.	1993-10	8397295

Patents

Sample Use Guides

In Vivo Use Guide

Induction of general anesthesia in cats: range 2.2 - 9.7 mg/kg for cats that did not receive a preanesthetic and 1.0 - 10.8 mg/kg for cats that received a preanesthetic. Induction of general anesthesia in dogs: range 1.5 - 4.5 mg/kg for dogs that did not receive a preanesthetic and between 0.2 - 3.5 mg/kg for dogs that received a preanesthetic.

Route of Administration: Intravenous

In Vitro Use Guide

Alfaxalone at a concentration of 50 uM reversibly blocked ongoing Seizure like events (SLEs) in organotypic hippocampal slice cultures. At a concentration of 20 uM it did not block ongoing SLEs but significantly reduced strength and duration of SLEs.

Substance Class	Chemical Created by `admin` on `Mon Mar 31 17:58:07 GMT 2025` Edited by `admin` on `Mon Mar 31 17:58:07 GMT 2025`
Record UNII	BD07M97B2A
Record Status	`Validated (UNII)`
Record Version

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Name

Type

Language

PHAXAN

Preferred Name

English

ALFAXALONE

Official Name

English

ALFAXALONE [GREEN BOOK]

Common Name

English

Alphaxolone

Common Name

English

GR 2/234

Code

English

ALFAXALONE [JAN]

Common Name

English

GR-2/234

Code

English

Alphaxalone

Common Name

English

ALPHAXALONE

Common Name

English

ALFAXALONE [MI]

Common Name

English

alfaxalone [INN]

Common Name

English

ALFAXALONE [MART.]

Common Name

English

Alfaxalone [WHO-DD]

Common Name

English

3.ALPHA.-HYDROXY-5.ALPHA.-PREGNANE-11,20-DIONE

Systematic Name

English

Classification Tree Code System Code

NCI_THESAURUS

C245