METAXALONE

Details

Stereochemistry	RACEMIC
Molecular Formula	C12H15NO3
Molecular Weight	221.2524
Optical Activity	( + / - )
Defined Stereocenters	0 / 1
E/Z Centers	0
Charge	0

SHOW SMILES / InChI

Structure Search

SMILES

CC1=CC(OCC2CNC(=O)O2)=CC(C)=C1

InChI

InChIKey=IMWZZHHPURKASS-UHFFFAOYSA-N

InChI=1S/C12H15NO3/c1-8-3-9(2)5-10(4-8)15-7-11-6-13-12(14)16-11/h3-5,11H,6-7H2,1-2H3,(H,13,14)

HIDE SMILES / InChI

Molecular Formula	C12H15NO3
Molecular Weight	221.2524
Charge	0
Count

Stereochemistry	RACEMIC
Additional Stereochemistry	No
Defined Stereocenters	0 / 1
E/Z Centers	0
Optical Activity	( + / - )

Description
Sources: http://www.accessdata.fda.gov/drugsatfda_docs/label/2015/022503s000lbl.pdf
Curator's Comment: description was created based on several sources, including: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=da237968-1c52-47c3-986b-4f878bd6b173 http://www.drugbank.ca/drugs/DB00660 https://en.wikipedia.org/wiki/Metaxalone

Metaxalone (marketed by King Pharmaceuticals under the brand name Skelaxin) is a muscle relaxant used to relax muscles and relieve pain caused by strains, sprains, and other musculoskeletal conditions. The mechanism of action of metaxalone in humans has not been established, but may be due to general central nervous system depression. Metaxalone has no direct action on the contractile mechanism of striated muscle, the motor end plate, or the nerve fiber. Skelaxin is available in an 800 mg scored tablet. Metaxalone relatively low incidence of side effects. The most common adverse reactions to Metaxalone tablets include drowsiness, dizziness, headache, and nervousness or “irritability”, nausea, vomiting, gastrointestinal upset.

CNS Activity

Originator

Approval Year

Targets

Primary Target	Pharmacology	Condition	Potency
central nervous system 1 Target ID: central nervous system Sources: http://www.accessdata.fda.gov/drugsatfda_docs/label/2015/022503s000lbl.pdf	Inhibitor 8504

Conditions

Condition	Modality	Targets	Highest Phase	Product
Painful musculoskeletal conditions 3 Sources: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=da237968-1c52-47c3-986b-4f878bd6b173	Secondary		Approved 8583	METAXALONE Approved Use are indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomforts associated with acute, painful musculoskeletal conditions Launch Date 1963

C_max

Value	Dose	Analyte	Population
983 ng/mL DRUG LABEL https://www.accessdata.fda.gov/drugsatfda_docs/label/2006/013217s046lbl.pdf	400 mg single, oral dose: 400 mg route of administration: Oral experiment type: SINGLE co-administered:	METAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: FASTED
1816 ng/mL DRUG LABEL https://www.accessdata.fda.gov/drugsatfda_docs/label/2006/013217s046lbl.pdf	800 mg single, oral dose: 800 mg route of administration: Oral experiment type: SINGLE co-administered:	METAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: FASTED
1816 ng/mL DRUG LABEL https://www.accessdata.fda.gov/drugsatfda_docs/label/2006/013217s046lbl.pdf	800 mg single, oral dose: 800 mg route of administration: Oral experiment type: SINGLE co-administered:	METAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: FASTED
3510 ng/mL DRUG LABEL https://www.accessdata.fda.gov/drugsatfda_docs/label/2006/013217s046lbl.pdf	800 mg single, oral dose: 800 mg route of administration: Oral experiment type: SINGLE co-administered:	METAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: FED

AUC

Value	Dose	Analyte	Population
7479 ng × h/mL DRUG LABEL https://www.accessdata.fda.gov/drugsatfda_docs/label/2006/013217s046lbl.pdf	400 mg single, oral dose: 400 mg route of administration: Oral experiment type: SINGLE co-administered:	METAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: FASTED
15044 ng × h/mL DRUG LABEL https://www.accessdata.fda.gov/drugsatfda_docs/label/2006/013217s046lbl.pdf	800 mg single, oral dose: 800 mg route of administration: Oral experiment type: SINGLE co-administered:	METAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: FASTED
15045 ng × h/mL DRUG LABEL https://www.accessdata.fda.gov/drugsatfda_docs/label/2006/013217s046lbl.pdf	800 mg single, oral dose: 800 mg route of administration: Oral experiment type: SINGLE co-administered:	METAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: FASTED
20833 ng × h/mL DRUG LABEL https://www.accessdata.fda.gov/drugsatfda_docs/label/2006/013217s046lbl.pdf	800 mg single, oral dose: 800 mg route of administration: Oral experiment type: SINGLE co-administered:	METAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: FED

T_1/2

Value	Dose	Co-administered	Analyte	Population
9 h DRUG LABEL https://www.accessdata.fda.gov/drugsatfda_docs/label/2006/013217s046lbl.pdf	400 mg single, oral dose: 400 mg route of administration: Oral experiment type: SINGLE co-administered:		METAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: FASTED
8 h DRUG LABEL https://www.accessdata.fda.gov/drugsatfda_docs/label/2006/013217s046lbl.pdf	800 mg single, oral dose: 800 mg route of administration: Oral experiment type: SINGLE co-administered:		METAXALONE plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: FASTED

Doses

Dose	Population	Adverse events
800 mg 4 times / day multiple, oral Dose: 800 mg, 4 times / day Route: oral Route: multiple Dose: 800 mg, 4 times / day Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf	unhealthy Health Status: unhealthy Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf	Disc. AE: Serotonin syndrome... AEs leading to discontinuation/dose reduction: Serotonin syndrome Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf

AEs

AE	Significance	Dose	Population
Serotonin syndrome	Disc. AE	800 mg 4 times / day multiple, oral Dose: 800 mg, 4 times / day Route: oral Route: multiple Dose: 800 mg, 4 times / day Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf	unhealthy Health Status: unhealthy Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf

Overview

CYP3A4	CYP2C9	CYP2D6	hERG
substrate 1946 inhibitor 2252 inducer 1087	substrate 1193 inhibitor 2438	substrate 1388 inhibitor 2507

OverviewOther

Other Inhibitor	Other Substrate	Other Inducer
CYP1A2 2153 CYP2A6 879 CYP2B6 926 CYP2C8 1057 CYP2C19 2057 CYP2E1 1060	CYP1A2 1197 CYP2E1 729 CYP2C8 810 CYP2C19 1119 P-gp 2052	CYP1A2 832 CYP2B6 669

Drug as perpetrator

Target	Modality	Activity
CYP1A2 2333	inducer 1966 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP1A2 2333	inhibitor 4027 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP2A6 911	inhibitor 4027 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP2B6 1160	inducer 1966 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP2B6 1160	inhibitor 4027 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP2C19 2141	inhibitor 4027 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP2C8 1117	inhibitor 4027 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP2C9 2497	inhibitor 4027 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP2D6 2546	inhibitor 4027 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP2E1 1146	inhibitor 4027 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP3A4 2633	inducer 1966 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no
CYP3A4 2633	inhibitor 4027 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	no

Drug as victim

Target	Modality	Activity
P-gp 2052	substrate 4014 Sources: https://link.springer.com/article/10.1007/s11095-018-2434-1 Page: 7.0	no
CYP2C19 1119	substrate 4014 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	weak
CYP2C8 810	substrate 4014 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	weak
CYP2C9 1193	substrate 4014 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	weak
CYP1A2 1197	substrate 4014 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	yes
CYP2D6 1388	substrate 4014 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	yes
CYP2E1 729	substrate 4014 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	yes
CYP3A4 1946	substrate 4014 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/013217s057lbl.pdf Page: 3.0	yes

Sourcing

Vendor/Aggregator	ID	URL
001 Chemical	NO13803	https://www.001chemical.com/chem/1665-48-1
3B Scientific (Wuhan) Corp	3B2-1432	http://www.3bsc.com/index/pro_info.php?id=55148
AA Blocks	AA001WP7	https://www.aablocks.com/goods/Goods/detail?id=AA001WP7
Aaron Chemicals	AR001XGZ	http://www.aaronchem.com/1665-48-1
abcr GmbH	AB449555	http://www.abcr.com/shop/en/AB449555
AbMole Bioscience	M5775	http://www.abmole.com/products/metaxalone.html
Acadechem	ACDS-026399	http://www.acadechemical.com/product/101098
Accela ChemBio Inc	SY052772	http://www.accelachem.com/cn/search.html?keyword=SY052772&attname=GoodsCode
Achemo Scientific Limited	AC-19046	http://www.achemo.com/search/?Keyword= 1665-48-1
Achemtek	0104-006050	http://www.achemtek.com/1665-48-1
AEchem Scientific Corp., USA	AE1-012775	http://www.aechemsc.com/info_products/AE1-012775.php
AHH Chemical co.,ltd	MT-53531	http://www.ahhchemical.com/product/MT-53531.html
Alfa Chemistry	AP1665481-A	https://reagents.alfa-chemistry.com/product/metaxalone-solution-cas-1665-48-1-6193.html
Alfa Chemistry	AP1665481-B	https://reagents.alfa-chemistry.com/product/metaxalone-cas-1665-48-1-6194.html
Alfa Chemistry	AP1665481-C	https://reagents.alfa-chemistry.com/product/metaxalone-cas-1665-48-1-6195.html
Alsachim	3406	http://www.alsachim.com/product-C4694-glo.bal-view.html
Ambeed	A718995	https://www.ambeed.com/products/1665-48-1.html
Angel Pharmatech	AG309216	http://www.angelpharmatech.com/1665-48-1.html
Angene	AGN-PC-0510QB	http://www.angenechemical.com/productshow/AGN-PC-0510QB.html
Ark Pharm	AK-61006	http://www.arkpharminc.com/products/1665-48-1.html
AstaTech, Inc.	25588	http://www.astatechinc.com/CPSResult.php?CRNO=28809
Aurum Pharmatech LLC	S-2010	http://www.Aurumpharmatech.com/Product/ProductDetails/S_2010
AvaChem Scientific	4607	http://www.avachem.com/productSearch.asp?4607
BioChemPartner	BCP28377	http://www.biochempartner.com/1665-48-1-BCP28377
BioCrick	BCC5223	http://www.biocrick.com/Metaxalone-BCC5223.html
BioSynth	J-010295	https://www.biosynth.com/en/products/all-products/products/J-010295.html
BLD Pharm	BD18774	http://www.bldpharm.com/products/1665-48-1.html
Boerchem	BC220747	http://www.boerchem.com/?product_37362.html
Chem Scene	CS-2910	http://www.chemscene.com/1665-48-1.html
Chemenu	CM110649	http://www.chemenu.com/products/CM110649
ChemMol	44006488	http://www.chemmol.com/chemmol/44006488.html
ChemMol	49430143	http://www.chemmol.com/chemmol/49430143.html
Chemspace	CSSB00000273362	https://chem-space.com/CSSB00000273362
Clearsynth	CS-O-11689	https://www.clearsynth.com/en/CSO11689.html
CSNpharm	CSN12579	https://www.csnpharm.com/products/metaxalone.html
DC Chemicals	DC9563	http://www.dcchemicals.com/product_show-Metaxalone.html
Debye Scientific	DB-043656	http://www.debyesci.com/cas_1665-48-1.html
eNovation Chemicals	D665068	https://www.enovationchem.com/ProductDetails.asp?ProductID=D665068
eNovation Chemicals	D952529	https://www.enovationchem.com/ProductDetails.asp?ProductID=D952529
Finetech	FT-0603568	http://www.finetechnology-ind.com/prod/detail/pub/1665-48-1.html
Glentham Life Sciences	GP7512	http://www.glentham.com/products/product/GP7512/
Hairui	HR128800	http://www.hairuichem.com/en/product/1665-48-1.html
Huateng Pharma	F829873	http://en.huatengsci.com/product/Metaxalone.html
iChemical	EBD36878	http://www.ichemical.com/chemicals/cas-1665-48-1
Lab Network	LN00177283	https://labnetwork.com/frontend-app/p/#!/moleculedetails/LN00177283
Matrix Scientific	75959	https://www.matrixscientific.com/075959.html
mcule	MCULE-3101469866	https://mcule.com/MCULE-3101469866/
MedChem Express	HY-B0678	https://www.medchemexpress.com/Metaxalone.html
Molcore	CS13803	https://www.molcore.com/product/1665-48-1
MuseChem	I002176	https://www.musechem.com/product/I002176.html
Oakwood	79268	http://www.oakwoodchemical.com/ProductsList.aspx?CategoryID=-2&txtSearch=64442&ExtHyperLink=1
OChem	3916	http://www.ocheminc.com/index.php?act=psearch&pid=665M481
Parchem	29383	http://www.parchem.com/chemical-supplier-distributor/Metaxalone-019383.aspx
Parchem	29384	http://www.parchem.com/chemical-supplier-distributor/Metaxalone-019384.aspx
Selleck Chemicals	S3730	http://www.selleckchem.com/products/metaxalone.html
Sigma-Aldrich	1396149_USP	https://www.sigmaaldrich.com/catalog/product/usp/1396149?utm_source=pubchem&utm_campaign=pubchem_2017&utm_medium=referral
Sigma-Aldrich	M-074_CERILLIAN	https://www.sigmaaldrich.com/catalog/product/cerillian/m074?utm_source=pubchem&utm_campaign=pubchem_2017&utm_medium=referral
Sigma-Aldrich	SML0199_SIGMA	https://www.sigmaaldrich.com/catalog/product/sigma/sml0199?utm_source=pubchem&utm_campaign=pubchem_2017&utm_medium=referral
Sinfoo Biotech	S010742	http://www.sinfoobiotech.com/product/1014140
Smolecule	S535064	http://www.smolecule.com/products/s535064
TCI (Tokyo Chemical Industry)	M2578	http://www.tcichemicals.com/eshop/en/us/commodity/M2578/index.html
THE BioTek	bt-275095	https://www.thebiotek.com/product/inhibitors/bt-275095
Vitas-M Laboratory	STL450994	http://www.request.vitasmlab.com/index.php?option=com_search_stk&Itemid=22&stk=STL450994&?utm_source=pubchem&utm_medium=p_search_link&utm_campaign=pubchem_search&utm_content=pubchem_slink
Vitas-M Laboratory	STL451511	http://www.request.vitasmlab.com/index.php?option=com_search_stk&Itemid=22&stk=STL451511&?utm_source=pubchem&utm_medium=p_search_link&utm_campaign=pubchem_search&utm_content=pubchem_slink
Yuhao Chemical	RT16589	http://www.chemyuhao.com/1665-48-1.html

PubMed

Title	Date	PubMed
Development of a list of potentially inappropriate drugs for the korean elderly using the delphi method.	2010-12	21818443
Pharmaceutical factories as a source of drugs in water.	2010-09	20810348
Pharmaceutical formulation facilities as sources of opioids and other pharmaceuticals to wastewater treatment plant effluents.	2010-07-01	20521847
Pharmacologic management of chronic pain.	2010-06	20556211
Inappropriate prescribing in the hospitalized elderly patient: defining the problem, evaluation tools, and possible solutions.	2010-04-07	20396637
Pediatric metaxalone ingestions reported to Texas poison control centers, 2000-2007.	2010-01	20042913
Adult metaxalone ingestions reported to Texas poison control centers, 2000-2006.	2010-01	19933254
Drugs associated with more suicidal ideations are also associated with more suicide attempts.	2009-10-02	19798416
Fibromyalgia and myofascial pain syndrome-a dilemma.	2009-10	20640108
Choosing a skeletal muscle relaxant.	2008-08-01	18711953
HPLC-ESI-MS/MS validated method for simultaneous quantification of zopiclone and its metabolites, N-desmethyl zopiclone and zopiclone-N-oxide in human plasma.	2008-03-15	18313371
Steady state bioequivalence of generic and innovator formulations of stavudine, lamivudine, and nevirapine in HIV-infected Ugandan adults.	2008	19096711
High throughput LC-MS/MS method for simultaneous quantification of lamivudine, stavudine and nevirapine in human plasma.	2007-06-15	17481969
Synthesis of poly(ethylene glycol)-metaxalone conjugates and study of its controlled release in vitro.	2007-03-06	17067768
Quantification of metaxalone in human plasma by liquid chromatography coupled to tandem mass spectrometry.	2006-05	16803662
Postmortem distribution of tramadol, amitriptyline, and their metabolites in a suicidal overdose.	2005-08-18	16105270
A fatality involving metaxalone.	2005-05-10	15749367
Auditory hallucinations elicited by combined meclizine and metaxalone use at bedtime.	2004-11	15454584
Commonly used muscle relaxant therapies for acute low back pain: a review of carisoprodol, cyclobenzaprine hydrochloride, and metaxalone.	2004-09	15530999
Metaxalone (Skelaxin)-related death.	2004-09	15516312
Comparative efficacy and safety of skeletal muscle relaxants for spasticity and musculoskeletal conditions: a systematic review.	2004-08	15276195
Comparison of the dissolution of metaxalone tablets (Skelaxin) using USP Apparatus 2 and 3.	2004-02-06	15198527
Polydrug fatality involving metaxalone.	2003-03	12665007
Centrally acting oral skeletal muscle relaxants.	1980-10	6999895

Patents

Sample Use Guides

In Vivo Use Guide

The recommended dose for adults and children over 12 years of age is one 800 mg tablet three to four times a day.

Route of Administration: Oral

In Vitro Use Guide

Unknown

Substance Class	Chemical Created by `admin` on `Mon Mar 31 18:43:35 GMT 2025` Edited by `admin` on `Mon Mar 31 18:43:35 GMT 2025`
Record UNII	1NMA9J598Y
Record Status	`Validated (UNII)`
Record Version

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Name

Type

Language

METAXALONE

Official Name

English

FLEXURA

Preferred Name

English

SKELAXIN

Brand Name

English

metaxalone [INN]

Common Name

English

METAXALONE [MART.]

Common Name

English

NSC-170959

Code

English

METAXALONE [VANDF]

Common Name

English

2-OXAZOLIDINONE, 5-((3,5-DIMETHYLPHENOXY)METHYL)-

Systematic Name

English

METAXALONE [USP-RS]

Common Name

English

METAXALONE [ORANGE BOOK]

Common Name

English

Metaxalone [WHO-DD]

Common Name

English

AHR-438

Code

English

METAXALONE [USAN]

Common Name

English

METAXALONE [MI]

Common Name

English

METAXALONE [USP MONOGRAPH]

Common Name

English

ZORANE

Brand Name

English

5-[(3,5-Xylyloxy)methyl]-2-oxazolidinone

Systematic Name

English

METAXALONE [HSDB]

Common Name

English

Classification Tree Code System Code

NDF-RT

N0000175730