U.S. Department of Health & Human Services Divider Arrow National Institutes of Health Divider Arrow NCATS

Details

Stereochemistry ACHIRAL
Molecular Formula C7H4ClNO2
Molecular Weight 169.5654
Optical Activity NONE
Defined Stereocenters 0 / 0
E/Z Centers 0
Charge 0

SHOW SMILES / InChI
Structure of CHLORZOXAZONE

SMILES

c1cc2c(cc1Cl)nc(O)o2

InChI

InChIKey=TZFWDZFKRBELIQ-UHFFFAOYSA-N
InChI=1S/C7H4ClNO2/c8-4-1-2-6-5(3-4)9-7(10)11-6/h1-3H,(H,9,10)

HIDE SMILES / InChI

Description
Curator's Comment:: description was created based on several sources, including https://www.ncbi.nlm.nih.gov/mesh/68002753

Chlorzoxazone is a centrally acting central muscle relaxant with sedative properties. It is claimed to inhibit muscle spasm by exerting an effect primarily at the level of the spinal cord and subcortical areas of the brain where it inhibits multisynaptic reflex arcs involved in producing and maintaining skeletal muscle spasm of varied etiology. The clinical result is a reduction of the skeletal muscle spasm with relief of pain and increased mobility of the involved muscles. Chlorzoxazone is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions. The mode of action of this drug has not been clearly identified, but may be related to its sedative properties. Chlorzoxazone does not directly relax tense skeletal muscles in man.

Originator

Curator's Comment:: Marsh, D.F.; US. Patent 2,895,877; July 21, 1959; assigned to McNeil Laboratories, Inc.

Approval Year

Targets

Targets

Conditions

Conditions

ConditionModalityTargetsHighest PhaseProduct
Primary
CHLORZOXAZONE

Approved Use

INDICATIONS & USAGE SECTION Chlorzoxazone is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions. The mode of action of this drug has not been clearly identified, but may be related to its sedative properties. Chlorzoxazone does not directly relax tense skeletal muscles in man.

Launch Date

5.7870719E11
Cmax

Cmax

ValueDoseCo-administeredAnalytePopulation
36.3 μg/mL
750 mg single, oral
dose: 750 mg
route of administration: Oral
experiment type: SINGLE
co-administered: ACETAMINOPHEN
CHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
5.1 μg/mL
250 mg single, oral
dose: 250 mg
route of administration: Oral
experiment type: SINGLE
co-administered: QUERCETIN
CHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
3.45 μg/mL
250 mg single, oral
dose: 250 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
15 μg/mL
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
5.2 μg/mL
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: UNHEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
12.2 μg/mL
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: UNHEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
0.14 μg/mL
250 mg single, oral
dose: 250 mg
route of administration: Oral
experiment type: SINGLE
co-administered: QUERCETIN
6-HYDROXYCHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
0.2 μg/mL
250 mg single, oral
dose: 250 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
6-HYDROXYCHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
AUC

AUC

ValueDoseCo-administeredAnalytePopulation
4084 μg × h/mL
750 mg single, oral
dose: 750 mg
route of administration: Oral
experiment type: SINGLE
co-administered: ACETAMINOPHEN
CHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
16.69 μg × h/mL
250 mg single, oral
dose: 250 mg
route of administration: Oral
experiment type: SINGLE
co-administered: QUERCETIN
CHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
9.86 μg × h/mL
250 mg single, oral
dose: 250 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
43.5 mg × h/L
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
15.7 μg × h/mL
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: UNHEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
32.8 μg × h/mL
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: UNHEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
0.64 μg × h/mL
250 mg single, oral
dose: 250 mg
route of administration: Oral
experiment type: SINGLE
co-administered: QUERCETIN
6-HYDROXYCHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
0.95 μg × h/mL
250 mg single, oral
dose: 250 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
6-HYDROXYCHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
T1/2

T1/2

ValueDoseCo-administeredAnalytePopulation
1.12 h
750 mg single, oral
dose: 750 mg
route of administration: Oral
experiment type: SINGLE
co-administered: ACETAMINOPHEN
CHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
1.65 h
250 mg single, oral
dose: 250 mg
route of administration: Oral
experiment type: SINGLE
co-administered: QUERCETIN
CHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
1.21 h
250 mg single, oral
dose: 250 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: MALE
food status: FASTED
1.1 h
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
1.4 h
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: UNHEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
1.2 h
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: UNHEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
Funbound

Funbound

ValueDoseCo-administeredAnalytePopulation
3.9%
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
3.2%
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: UNHEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
4%
500 mg single, oral
dose: 500 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
CHLORZOXAZONE serum
Homo sapiens
population: UNHEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
Overview

Overview

CYP3A4CYP2C9CYP2D6hERG

OverviewOther

Other InhibitorOther SubstrateOther Inducer



Drug as victim
PubMed

PubMed

TitleDatePubMed
Mechanism of aerobic transformation of carbon tetrachloride by poplar cells.
2002
Fondaparinux sodium is not metabolised in mammalian liver fractions and does not inhibit cytochrome P450-mediated metabolism of concomitant drugs.
2002
Validated HPLC method for determination of chlorzoxazone in human serum and its application in a clinical pharmacokinetic study.
2002 Dec
Potentiation of 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123)-induced liver toxicity by ethanol in guinea-pigs.
2002 Dec
Evaluation of cytochrome P450 probe substrates commonly used by the pharmaceutical industry to study in vitro drug interactions.
2002 Dec
[Simultaneous determination of three probe drugs by reversed-phase high performance liquid chromatography].
2002 Nov
Phenotype distribution and gender-related differences of CYP2E1 activity in a Chinese population.
2002 Nov
Monolithic silica rod liquid chromatography with ultraviolet or fluorescence detection for metabolite analysis of cytochrome P450 marker reactions.
2002 Nov 25
Conformational changes in nitric oxide synthases induced by chlorzoxazone and nitroindazoles: crystallographic and computational analyses of inhibitor potency.
2002 Nov 26
Cytochrome P450 2E1 expression induces hepatocyte resistance to cell death from oxidative stress.
2002 Oct
Plasma levels of TNF-alpha and IL-6 are inversely related to cytochrome P450-dependent drug metabolism in patients with congestive heart failure.
2002 Oct
Metabolizing enzyme localization and activities in the first trimester human placenta: the effect of maternal and gestational age, smoking and alcohol consumption.
2002 Oct
Inhibition of cytochrome P450 2E1 by propofol in human and porcine liver microsomes.
2002 Oct 1
Watercress has no Importance for the elimination of ethanol by CYP2E1 inhibition.
2002 Sep
Cytochrome P450 2E1 and 3A activities do not differ between Mexicans and European Americans.
2002 Sep
Cytochrome P450 phenotypic ratios for predicting herb-drug interactions in humans.
2002 Sep
Kinetic study of alkaline induced hydrolysis of the skeletal muscle relaxant chlorzoxazone using ratio spectra first derivative spectrophotometry.
2003 Apr
The cytochrome P-450 isoenzyme CYP2E1 in the biological processing of industrial chemicals: consequences for occupational and environmental medicine.
2003 Apr
Cytochrome P450 2E1 genotype and the susceptibility to antituberculosis drug-induced hepatitis.
2003 Apr
Lipopolysaccharide-mediated modulation of cytochromes P450 in Stat1 null mice.
2003 Apr
Construction and assessment of models of CYP2E1: predictions of metabolism from docking, molecular dynamics, and density functional theoretical calculations.
2003 Apr 24
Phorbol ester induces CYP2E1 in astrocytes, through a protein kinase C- and tyrosine kinase-dependent mechanism.
2003 Aug
Effects of glucose on the pharmacokinetics of intravenous chlorzoxazone in rats with acute renal failure induced by uranyl nitrate.
2003 Aug
CYP2E1 activity before and after weight loss in morbidly obese subjects with nonalcoholic fatty liver disease.
2003 Aug
Rates of metabolism of chlorzoxazone, dextromethorphan, 7-ethoxycoumarin, imipramine, quinidine, testosterone and verapamil by fresh and cryopreserved rat liver slices, and some comparisons with microsomes.
2003 Aug
Characterization of vectorial chloride transport pathways in the human pancreatic duct adenocarcinoma cell line HPAF.
2003 Aug
Simultaneous determination of aspirin and isosorbide 5-mononitrate in formulation by reversed phase high pressure liquid chromatography.
2003 Aug 21
Study of the fragmentation mechanism of protonated 6-hydroxychlorzoxazone: application in simultaneous analysis of CYP2E1 activity with major human cytochrome P450s.
2003 Feb 1
Diabetes mellitus increases the in vivo activity of cytochrome P450 2E1 in humans.
2003 Jan
Essential requirements for substrate binding affinity and selectivity toward human CYP2 family enzymes.
2003 Jan 1
Determination of 6-hydroxychlorzoxazone and chlorzoxazone in porcine microsome samples.
2003 Jan 25
Stimulatory effects of chlorzoxazone, a centrally acting muscle relaxant, on large conductance calcium-activated potassium channels in pituitary GH3 cells.
2003 Jan 3
Unexpected down-regulation of the hIK1 Ca2+-activated K+ channel by its opener 1-ethyl-2-benzimidazolinone in HaCaT keratinocytes. Inverse effects on cell growth and proliferation.
2003 Jan 31
Maintenance of liver functions in rat hepatocytes cultured as spheroids in a rotating wall vessel.
2003 Jan-Feb
Differential inhibition of human cytochrome P450 enzymes by epsilon-viniferin, the dimer of resveratrol: comparison with resveratrol and polyphenols from alcoholized beverages.
2003 Jul 18
Diterpene quinone tanshinone IIA selectively inhibits mouse and human cytochrome p4501A2.
2003 Jun
Functional characterization of three human cytochrome p450 2E1 variants with amino acid substitutions.
2003 Jun
How useful is the "cocktail approach" for evaluating human hepatic drug metabolizing capacity using cytochrome P450 phenotyping probes in vivo?
2003 Jun
Effects of acute renal failure on the pharmacokinetics of chlorzoxazone in rats.
2003 Jun
Effects of recombinant human growth hormone on the pharmacokinetics of intravenous chlorzoxazone in rats with acute renal failure induced by uranyl nitrate.
2003 Jun 6
Isozyme-specific induction of low-dose aspirin on cytochrome P450 in healthy subjects.
2003 Mar
Pharmacokinetics of intravenous chlorzoxazone in rats with dehydration and rehydration: effects of food intakes.
2003 Mar
Hepatic cytochrome P450 2E1 activity in nondiabetic patients with nonalcoholic steatohepatitis.
2003 Mar
Metabolism of chloroform in the human liver and identification of the competent P450s.
2003 Mar
Cytochrome P450 expression and testosterone metabolism in the liver of deer.
2003 May 1
Effects of cigarette smoking and carbon monoxide on chlorzoxazone and caffeine metabolism.
2003 Nov
Mechanism-based inhibition of human liver microsomal cytochrome P450 1A2 by zileuton, a 5-lipoxygenase inhibitor.
2003 Nov
GYKI-47261, a new AMPA [2-amino-3-(3-hydroxymethylisoxazole-4-yl)propionic acid] antagonist, is a CYP2E1 inducer.
2003 Nov
CYP2E1 regulation by benzene and other small organic chemicals in rat liver and peripheral lymphocytes.
2003 Sep 15
ATP release triggered by activation of the Ca2+-activated K+ channel in human airway Calu-3 cells.
2004 Mar
Patents

Sample Use Guides

One tablet three or four times daily. If adequate response is not obtained with this dose, it may be increased to one and one-half tablets (750 mg) three or four times daily. As improvement occurs dosage can usually be reduced.
Route of Administration: Oral
Chlorzoxazone did not affect the tension of the rat thoracic artery rings at rest, but relaxed the precontraction induced by 1 uM noradrenaline in an endothelium independent manner. Preincubation with chlorzoxazone also antagonized the contraction induced by 1 uM noradrenaline or 25 mM KCl.
Name Type Language
CHLORZOXAZONE
INN   JAN   MART.   MI   ORANGE BOOK   USP   USP-RS   VANDF   WHO-DD  
INN  
Official Name English
CHLORZOXAZONE [MART.]
Common Name English
CHLORZOXAZONE [INN]
Common Name English
CHLORZOXAZONE [USP]
Common Name English
CHLORZOXAZONE [USP-RS]
Common Name English
5-CHLORO-2-BENZOXAZOLINONE
Systematic Name English
STRIFON
Brand Name English
CHLORZOXAZONE [JAN]
Common Name English
PARAFLEX
Brand Name English
CHLORZOXAZONE [MI]
Common Name English
CHLORZOXAZONE [ORANGE BOOK]
Common Name English
PARAFON
Brand Name English
CHLORZOXAZONE [VANDF]
Common Name English
CHLORZOXAZONE [WHO-DD]
Common Name English
CHLORZOXAZONE [USP MONOGRAPH]
Common Name English
2(3H)-BENZOXAZOLONE, 5-CHLORO-
Systematic Name English
Classification Tree Code System Code
LIVERTOX 200
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
NDF-RT N0000175737
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
WHO-VATC QM03BB53
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
WHO-ATC M03BB03
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
WHO-VATC QM03BB03
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
WHO-ATC M03BB53
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
NDF-RT N0000175730
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
WHO-ATC M03BB73
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
NCI_THESAURUS C29696
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
WHO-VATC QM03BB73
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
Code System Code Type Description
ECHA (EC/EINECS)
202-403-9
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY
EPA CompTox
95-25-0
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PRIMARY
MESH
D002753
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PRIMARY
USP_CATALOG
1130505
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY USP-RS
FDA UNII
H0DE420U8G
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PRIMARY
IUPHAR
2322
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PRIMARY
CAS
95-25-0
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY
EVMPD
SUB06215MIG
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY
WIKIPEDIA
CHLORZOXAZONE
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY
RXCUI
2410
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY RxNorm
ChEMBL
CHEMBL1371
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY
INN
748
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY
MERCK INDEX
M3471
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY Merck Index
NCI_THESAURUS
C28926
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY
DRUG CENTRAL
626
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY
PUBCHEM
2733
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY
DRUG BANK
DB00356
Created by admin on Fri Jun 25 20:58:15 UTC 2021 , Edited by admin on Fri Jun 25 20:58:15 UTC 2021
PRIMARY