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Details

Stereochemistry RACEMIC
Molecular Formula C12H15NO3
Molecular Weight 221.2529
Optical Activity ( + / - )
Defined Stereocenters 0 / 1
E/Z Centers 0
Charge 0

SHOW SMILES / InChI
Structure of METAXALONE

SMILES

Cc1cc(C)cc(c1)OCC2CN=C(O)O2

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

Description
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

Curator's Comment:: CNS depressant used for acute musculoskeletal spasmodic pain.

Originator

Curator's Comment:: Metaxalone was first discovered in the 1960s, and had been sold under the brand name Skelaxin since 1962 -- first by A.H. Robins Co., then by Elan Pharma, Inc ('Elan'), and finally by King.

Approval Year

Targets

Targets

Primary TargetPharmacologyConditionPotency
Conditions

Conditions

ConditionModalityTargetsHighest PhaseProduct
Secondary
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

-2.20320006E11
Cmax

Cmax

ValueDoseCo-administeredAnalytePopulation
1816 ng/mL
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
983 ng/mL
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
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
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

AUC

ValueDoseCo-administeredAnalytePopulation
15044 ng × h/mL
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
7479 ng × h/mL
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
15045 ng × h/mL
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
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
T1/2

T1/2

ValueDoseCo-administeredAnalytePopulation
8 h
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
9 h
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
Doses

Doses

DosePopulationAdverse events​
800 mg 4 times / day multiple, oral
Dose: 800 mg, 4 times / day
Route: oral
Route: multiple
Dose: 800 mg, 4 times / day
Co-administed with::
Serotonergic drugs
Sources:
unhealthy
Disc. AE: Serotonin syndrome...
AEs leading to
discontinuation/dose reduction:
Serotonin syndrome
Sources:
AEs

AEs

AESignificanceDosePopulation
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
Co-administed with::
Serotonergic drugs
Sources:
unhealthy
OverviewDrug as perpetrator​

Drug as perpetrator​

TargetModalityActivityMetaboliteClinical evidence
no
no
no
no
no
no
no
no
no
no
no
no
Drug as victim
Sourcing

Sourcing

Vendor/AggregatorIDURL
PubMed

PubMed

TitleDatePubMed
Centrally acting oral skeletal muscle relaxants.
1980 Oct
Polydrug fatality involving metaxalone.
2003 Mar
Comparative efficacy and safety of skeletal muscle relaxants for spasticity and musculoskeletal conditions: a systematic review.
2004 Aug
Comparison of the dissolution of metaxalone tablets (Skelaxin) using USP Apparatus 2 and 3.
2004 Feb 6
Auditory hallucinations elicited by combined meclizine and metaxalone use at bedtime.
2004 Nov
Commonly used muscle relaxant therapies for acute low back pain: a review of carisoprodol, cyclobenzaprine hydrochloride, and metaxalone.
2004 Sep
Metaxalone (Skelaxin)-related death.
2004 Sep
Postmortem distribution of tramadol, amitriptyline, and their metabolites in a suicidal overdose.
2005 Jul-Aug
A fatality involving metaxalone.
2005 May 10
High throughput LC-MS/MS method for simultaneous quantification of lamivudine, stavudine and nevirapine in human plasma.
2007 Jun 15
Steady state bioequivalence of generic and innovator formulations of stavudine, lamivudine, and nevirapine in HIV-infected Ugandan adults.
2008
Choosing a skeletal muscle relaxant.
2008 Aug 1
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 Mar 15
Fibromyalgia and myofascial pain syndrome-a dilemma.
2009 Oct
Drugs associated with more suicidal ideations are also associated with more suicide attempts.
2009 Oct 2
Inappropriate prescribing in the hospitalized elderly patient: defining the problem, evaluation tools, and possible solutions.
2010 Apr 7
Development of a list of potentially inappropriate drugs for the korean elderly using the delphi method.
2010 Dec
Pediatric metaxalone ingestions reported to Texas poison control centers, 2000-2007.
2010 Jan
Adult metaxalone ingestions reported to Texas poison control centers, 2000-2006.
2010 Jan
Pharmaceutical formulation facilities as sources of opioids and other pharmaceuticals to wastewater treatment plant effluents.
2010 Jul 1
Pharmacologic management of chronic pain.
2010 Jun
Pharmaceutical factories as a source of drugs in water.
2010 Sep
Patents

Sample Use Guides

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
Name Type Language
METAXALONE
HSDB   INN   MART.   MI   ORANGE BOOK   USAN   USP-RS   VANDF   WHO-DD  
INN   USAN  
Official 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
FLEXURA
Brand Name English
METAXALONE [ORANGE BOOK]
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
METAXALONE [WHO-DD]
Common 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
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
LIVERTOX 609
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
NDF-RT N0000175737
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
NCI_THESAURUS C29696
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
Code System Code Type Description
ECHA (EC/EINECS)
216-777-6
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
EVMPD
SUB08817MIG
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
USP_CATALOG
1396149
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY USP-RS
PUBCHEM
15459
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
DRUG CENTRAL
1722
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
WIKIPEDIA
METAXALONE
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
EPA CompTox
1665-48-1
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
MERCK INDEX
M322
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY Merck Index
HSDB
3236
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
CAS
105801-80-7
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
SUPERSEDED
FDA UNII
1NMA9J598Y
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
CAS
1665-48-1
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
IUPHAR
7609
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
MESH
C011301
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
INN
1027
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
ChEMBL
CHEMBL1079604
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
RXCUI
59078
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY RxNorm
DRUG BANK
DB00660
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY
NCI_THESAURUS
C47606
Created by admin on Sat Jun 26 11:03:45 UTC 2021 , Edited by admin on Sat Jun 26 11:03:45 UTC 2021
PRIMARY