Identification

Name
Chlorzoxazone
Accession Number
DB00356
Description

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. (From Martindale, The Extra Pharmacopoea, 30th ed, p1202)

Type
Small Molecule
Groups
Approved
Structure
Thumb
Weight
Average: 169.565
Monoisotopic: 168.993056084
Chemical Formula
C7H4ClNO2
Synonyms
  • 2-hydroxy-5-chlorobenzoxazole
  • 5-chloro-2-benzoxazolinone
  • 5-chloro-2-benzoxazolol
  • 5-chloro-2-benzoxazolone
  • 5-chloro-2-hydroxybenzoxazole
  • 5-chloro-2(3H)-benzoxazolone
  • 5-chloro-3H-benzooxazol-2-one
  • 5-chlorobenzoxazolidone
  • 5-chlorobenzoxazolin-2-one
  • Chlorzoxane
  • Chlorzoxazon
  • Chlorzoxazona
  • Chlorzoxazone
  • Chlorzoxazonum
  • Clorzoxazona
  • Clorzoxazone
External IDs
  • MI 315
  • USAF MA-10

Pharmacology

Indication

For the relief of discomfort associated with acute painful musculoskeletal conditions.

Associated Conditions
Contraindications & Blackbox Warnings
Learn about our commercial Contraindications & Blackbox Warnings data.
Learn More
Pharmacodynamics

Chlorzoxazone is a centrally-acting agent for painful musculoskeletal conditions. Data available from animal experiments as well as human study indicate that chlorzoxazone acts primarily at the level of the spinal cord and subcortical areas of the brain where it inhibits multisynaptic reflex a.c. 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.

Mechanism of action

Chlorzoxazone inhibits degranulation of mast cells, subsequently preventing the release of histamine and slow-reacting substance of anaphylaxis (SRS-A), mediators of type I allergic reactions. Chlorzoxazone also may reduce the release of inflammatory leukotrienes. Chlorzoxazone may act by inhibiting calcium and potassium influx which would lead to neuronal inhibition and muscle relaxation. Data available from animal experiments as well as human study indicate that chlorzoxazone acts 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

TargetActionsOrganism
ACalcium-activated potassium channel subunit alpha-1Not AvailableHumans
Absorption
Not Available
Volume of distribution
Not Available
Protein binding

13-18%

Metabolism

Chlorzoxazone is rapidly metabolized in the liver and is excreted in the urine, primarily in a conjugated form as the glucuronide.

Hover over products below to view reaction partners

Route of elimination

Chlorzoxazone is rapidly metabolized and is excreted in the urine, primarily in a conjugated form as the glucuronide.

Half-life
Not Available
Clearance
Not Available
Adverse Effects
Learn about our commercial Adverse Effects data.
Learn More
Toxicity

Oral, mouse: LD50 = 440 mg/kg; Oral, rat: LD50 = 763 mg/kg; Symptoms of overdose include diarrhea, dizziness, drowsiness, headache, light-headedness, nausea, and vomiting.

Affected organisms
  • Humans and other mammals
Pathways
Not Available
Pharmacogenomic Effects/ADRs
Not Available

Interactions

Drug Interactions
This information should not be interpreted without the help of a healthcare provider. If you believe you are experiencing an interaction, contact a healthcare provider immediately. The absence of an interaction does not necessarily mean no interactions exist.
DrugInteraction
AbacavirChlorzoxazone may decrease the excretion rate of Abacavir which could result in a higher serum level.
AbametapirThe serum concentration of Chlorzoxazone can be increased when it is combined with Abametapir.
AbataceptThe metabolism of Chlorzoxazone can be increased when combined with Abatacept.
AbirateroneThe serum concentration of Chlorzoxazone can be increased when it is combined with Abiraterone.
AcarboseAcarbose may decrease the excretion rate of Chlorzoxazone which could result in a higher serum level.
AcebutololThe metabolism of Chlorzoxazone can be decreased when combined with Acebutolol.
AceclofenacAceclofenac may decrease the excretion rate of Chlorzoxazone which could result in a higher serum level.
AcemetacinAcemetacin may decrease the excretion rate of Chlorzoxazone which could result in a higher serum level.
AcenocoumarolThe metabolism of Acenocoumarol can be decreased when combined with Chlorzoxazone.
AcetazolamideThe risk or severity of adverse effects can be increased when Chlorzoxazone is combined with Acetazolamide.
Additional Data Available
  • Extended Description
    Extended Description

    Extended description of the mechanism of action and particular properties of each drug interaction.

    Learn more
  • Severity
    Severity

    A severity rating for each drug interaction, from minor to major.

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  • Evidence Level
    Evidence Level

    A rating for the strength of the evidence supporting each drug interaction.

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  • Action
    Action

    An effect category for each drug interaction. Know how this interaction affects the subject drug.

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Food Interactions
  • Avoid alcohol.
  • Take with or without food. The absorption is unaffected by food.

Products

Product Images
International/Other Brands
Myoflexin (Zentiva) / Paraflex (BioPhausia) / Relaxazone / Remular / Remular-S / Solaxin (Eisai) / Strifon Forte DSC
Brand Name Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing EndRegionImage
Parafon ForteTablet500 mg/1OralOrtho-McNeil Pharmaceutical, Inc.1958-08-152013-05-31US flag
Parafon Forte DSCTablet500 mg/1OralJanssen Pharmaceuticals1987-06-152017-10-31US flag
Parafon Forte DSCTablet500 mg/1OralRemedy Repack2016-11-072016-11-07US flag
Additional Data Available
  • Application Number
    Application Number

    A unique ID assigned by the FDA when a product is submitted for approval by the labeller.

    Learn more
  • Product Code
    Product Code

    A governmentally-recognized ID which uniquely identifies the product within its regulatory market.

    Learn more
Generic Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing EndRegionImage
ChlorzoxazoneTablet500 mg/1OralAidarex Pharmaceuticals LLC2011-08-22Not applicableUS flag
ChlorzoxazoneTablet500 mg/1OralClinical Solutions Wholsesale2011-08-222017-06-28US flag00591 2520 01 nlmimage10 b73a5bf2
ChlorzoxazoneTablet375 ug/1OralCameron Pharmaceuticals2019-11-27Not applicableUS flag
ChlorzoxazoneTablet500 mg/1OralLake Erie Medical DBA Quality Care Products LLC2011-04-12Not applicableUS flag
ChlorzoxazoneTablet500 mg/1OralREMEDYREPACK INC.2017-11-15Not applicableUS flag
ChlorzoxazoneTablet250 mg/1OralBasiem2019-07-302019-10-01US flag
ChlorzoxazoneTablet500 mg/1OralPhysicians Total Care, Inc.1995-04-24Not applicableUS flag
ChlorzoxazoneTablet500 mg/1OralMayne Pharma2020-07-31Not applicableUS flag
ChlorzoxazoneTablet500 mg/1OralH.J. Harkins Company2008-12-232013-01-31US flag
ChlorzoxazoneTablet500 mg/1OralBarr Laboratories1990-06-302013-10-31US flag
Additional Data Available
  • Application Number
    Application Number

    A unique ID assigned by the FDA when a product is submitted for approval by the labeller.

    Learn more
  • Product Code
    Product Code

    A governmentally-recognized ID which uniquely identifies the product within its regulatory market.

    Learn more
Mixture Products
NameIngredientsDosageRouteLabellerMarketing StartMarketing EndRegionImage
Acetazone ForteChlorzoxazone (250 mg) + Acetaminophen (300 mg)TabletOralTEVA Canada Limited1991-12-31Not applicableCanada flag
Acetazone Forte C8Chlorzoxazone (250 mg) + Acetaminophen (300 mg) + Codeine phosphate (8 mg)TabletOralTEVA Canada Limited1991-12-31Not applicableCanada flag
Back-aid Forte - TabChlorzoxazone (250 mg) + Acetaminophen (300 mg)TabletOralRougier Pharma Division Of Ratiopharm Inc1995-12-312015-10-01Canada flag
Extra Strength Tylenol Aches and StrainsChlorzoxazone (250 mg) + Acetaminophen (500 mg)TabletOralMcneil Consumer Healthcare Division Of Johnson & Johnson Inc1996-12-312008-08-07Canada flag
Gin Pain Pills - TabChlorzoxazone (250 mg) + Acetaminophen (300 mg)TabletOralStella Pharmaceutical Canada Inc.1996-09-052002-07-05Canada flag
Parafon ForteChlorzoxazone (250 mg) + Acetaminophen (300 mg)TabletOralMcneil Pharmaceutical, Division Of Ortho Mcneil Inc.1949-12-311999-08-12Canada flag
Parafon Forte C8 W Codeine TabChlorzoxazone (250 mg) + Acetaminophen (300 mg) + Codeine phosphate (8 mg)TabletOralMcneil Pharmaceutical, Division Of Ortho Mcneil Inc.1985-12-311999-11-09Canada flag
Parafon Forte TabletsChlorzoxazone (250 mg) + Acetaminophen (300 mg)TabletOralJohnson & Johnson Merck Consumer Pharmaceuticals Of Canada1997-07-312008-08-07Canada flag

Categories

ATC Codes
M03BB03 — ChlorzoxazoneM03BB53 — Chlorzoxazone, combinations excl. psycholepticsM03BB73 — Chlorzoxazone, combinations with psycholeptics
Drug Categories
Chemical TaxonomyProvided by Classyfire
Description
This compound belongs to the class of organic compounds known as benzoxazolones. These are organic compounds containing a benzene fused to an oxazole ring (a five-member aliphatic ring with three carbon atoms, one oxygen atom, and one nitrogen atom) bearing a ketone group.
Kingdom
Organic compounds
Super Class
Organoheterocyclic compounds
Class
Benzoxazoles
Sub Class
Benzoxazolones
Direct Parent
Benzoxazolones
Alternative Parents
Benzenoids / Aryl chlorides / Oxazoles / Heteroaromatic compounds / Oxacyclic compounds / Azacyclic compounds / Organopnictogen compounds / Organooxygen compounds / Organonitrogen compounds / Organochlorides
show 2 more
Substituents
Aromatic heteropolycyclic compound / Aryl chloride / Aryl halide / Azacycle / Azole / Benzenoid / Benzoxazolone / Heteroaromatic compound / Hydrocarbon derivative / Organic nitrogen compound
show 9 more
Molecular Framework
Aromatic heteropolycyclic compounds
External Descriptors
1,3-benzoxazoles, organochlorine compound, heteroaryl hydroxy compound (CHEBI:3655)

Chemical Identifiers

UNII
H0DE420U8G
CAS number
95-25-0
InChI Key
TZFWDZFKRBELIQ-UHFFFAOYSA-N
InChI
InChI=1S/C7H4ClNO2/c8-4-1-2-6-5(3-4)9-7(10)11-6/h1-3H,(H,9,10)
IUPAC Name
5-chloro-2,3-dihydro-1,3-benzoxazol-2-one
SMILES
ClC1=CC2=C(OC(=O)N2)C=C1

References

Synthesis Reference

Marsh, D.F.; US. Patent 2,895,877; July 21, 1959; assigned to McNeil Laboratories, Inc.

General References
  1. Dong DL, Luan Y, Feng TM, Fan CL, Yue P, Sun ZJ, Gu RM, Yang BF: Chlorzoxazone inhibits contraction of rat thoracic aorta. Eur J Pharmacol. 2006 Sep 18;545(2-3):161-6. Epub 2006 Jun 29. [PubMed:16859676]
  2. Park JY, Kim KA, Park PW, Ha JM: Effect of high-dose aspirin on CYP2E1 activity in healthy subjects measured using chlorzoxazone as a probe. J Clin Pharmacol. 2006 Jan;46(1):109-14. [PubMed:16397290]
  3. Wan J, Ernstgard L, Song BJ, Shoaf SE: Chlorzoxazone metabolism is increased in fasted Sprague-Dawley rats. J Pharm Pharmacol. 2006 Jan;58(1):51-61. [PubMed:16393464]
Human Metabolome Database
HMDB0014500
KEGG Drug
D00771
KEGG Compound
C07931
PubChem Compound
2733
PubChem Substance
46507755
ChemSpider
2632
BindingDB
50290811
RxNav
2410
ChEBI
3655
ChEMBL
CHEMBL1371
ZINC
ZINC000084843283
Therapeutic Targets Database
DAP000952
PharmGKB
PA448971
Guide to Pharmacology
GtP Drug Page
PDBe Ligand
CLW
RxList
RxList Drug Page
Drugs.com
Drugs.com Drug Page
PDRhealth
PDRhealth Drug Page
Wikipedia
Chlorzoxazone
PDB Entries
1m8d / 1m9j
MSDS
Download (61.8 KB)

Clinical Trials

Clinical Trials
PhaseStatusPurposeConditionsCount
4CompletedBasic ScienceAlcohol Abuse1
4CompletedBasic ScienceType 2 Diabetes Mellitus1
4CompletedTreatmentChlorzoxazone / Postoperative pain1
4CompletedTreatmentOsteoarthritis in the Hip Joint / Osteoarthritis of the Knee1
1CompletedBasic ScienceDrug Drug Interaction (DDI)1
1CompletedDiagnosticCytochrome / Pharmacokinetics1
Not AvailableCompletedTreatmentAlcohol Drinking / Attention Deficit Hyperactivity Disorder (ADHD) / Cessation, Smoking / Depression1

Pharmacoeconomics

Manufacturers
  • Actavis totowa llc
  • Barr laboratories inc
  • Mikart inc
  • Mutual pharmaceutical co inc
  • Ohm laboratories inc
  • Par pharmaceutical inc
  • Pioneer pharmaceuticals inc
  • Sandoz inc
  • Watson laboratories inc
  • Ortho mcneil pharmaceutical inc
  • Ortho mcneil janssen pharmaceuticals inc
  • Ferndale laboratories inc
Packagers
  • A-S Medication Solutions LLC
  • Barr Pharmaceuticals
  • Bryant Ranch Prepack
  • Deliz Pharmaceutical Corp.
  • Direct Dispensing Inc.
  • Dispensing Solutions
  • Diversified Healthcare Services Inc.
  • H.J. Harkins Co. Inc.
  • Innoviant Pharmacy Inc.
  • International Ethical Labs Inc.
  • Janssen-Ortho Inc.
  • Keltman Pharmaceuticals Inc.
  • Lake Erie Medical and Surgical Supply
  • Major Pharmaceuticals
  • McNeil Laboratories
  • Murfreesboro Pharmaceutical Nursing Supply
  • Nucare Pharmaceuticals Inc.
  • Ortho-McNeil-Janssen Pharmaceuticals Inc.
  • Palmetto Pharmaceuticals Inc.
  • Par Pharmaceuticals
  • PCA LLC
  • PD-Rx Pharmaceuticals Inc.
  • Pharmaceutical Utilization Management Program VA Inc.
  • Physicians Total Care Inc.
  • Preferred Pharmaceuticals Inc.
  • Prepackage Specialists
  • Prescript Pharmaceuticals
  • Rebel Distributors Corp.
  • Redpharm Drug
  • Scruggs Pharmacal Co. Inc.
  • Southwood Pharmaceuticals
  • Stat Rx Usa
  • Teva Pharmaceutical Industries Ltd.
  • UDL Laboratories
  • United Research Laboratories Inc.
  • Watson Pharmaceuticals
Dosage Forms
FormRouteStrength
TabletOral
TabletOcclusive dressing technique500 mg/1
TabletOral250 mg/1
TabletOral375 ug/1
TabletOral500 mg/1
TabletOral750 1/1
TabletOral750 ug/1
TabletOral750 mg/1
TabletOral375 mg/1
TabletOral250 mg
Tablet500 mg
Tablet250 mg
Tablet
Prices
Unit descriptionCostUnit
Parafon forte dsc 500 mg caplet2.65USD caplet
Chlorzoxazone 500 mg tablet0.87USD tablet
Chlorzoxazone 250 mg tablet0.18USD tablet
DrugBank does not sell nor buy drugs. Pricing information is supplied for informational purposes only.
Patents
Not Available

Properties

State
Solid
Experimental Properties
PropertyValueSource
melting point (°C)191-191.5Marsh, D.F.; US. Patent 2,895,877; July 21, 1959; assigned to McNeil Laboratories, Inc.
water solubility1000 mg/LNot Available
logP1.6Not Available
Predicted Properties
PropertyValueSource
Water Solubility2.96 mg/mLALOGPS
logP2.09ALOGPS
logP1.94ChemAxon
logS-1.8ALOGPS
pKa (Strongest Acidic)9.39ChemAxon
pKa (Strongest Basic)-2.2ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count2ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area38.33 Å2ChemAxon
Rotatable Bond Count0ChemAxon
Refractivity41.07 m3·mol-1ChemAxon
Polarizability14.94 Å3ChemAxon
Number of Rings2ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleNoChemAxon
Predicted ADMET Features
PropertyValueProbability
Human Intestinal Absorption+1.0
Blood Brain Barrier+0.991
Caco-2 permeable+0.5
P-glycoprotein substrateNon-substrate0.8733
P-glycoprotein inhibitor INon-inhibitor0.9784
P-glycoprotein inhibitor IINon-inhibitor0.9263
Renal organic cation transporterNon-inhibitor0.9001
CYP450 2C9 substrateNon-substrate0.8243
CYP450 2D6 substrateSubstrate0.6471
CYP450 3A4 substrateNon-substrate0.5372
CYP450 1A2 substrateInhibitor0.9107
CYP450 2C9 inhibitorNon-inhibitor0.9539
CYP450 2D6 inhibitorNon-inhibitor0.9338
CYP450 2C19 inhibitorNon-inhibitor0.9025
CYP450 3A4 inhibitorNon-inhibitor0.9522
CYP450 inhibitory promiscuityLow CYP Inhibitory Promiscuity0.8682
Ames testNon AMES toxic0.7957
CarcinogenicityNon-carcinogens0.9467
BiodegradationNot ready biodegradable0.9655
Rat acute toxicity2.2388 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.8675
hERG inhibition (predictor II)Non-inhibitor0.9659
ADMET data is predicted using admetSAR, a free tool for evaluating chemical ADMET properties. (23092397)

Spectra

Mass Spec (NIST)
Not Available
Spectra
SpectrumSpectrum TypeSplash Key
Predicted GC-MS Spectrum - GC-MSPredicted GC-MSNot Available
GC-MS Spectrum - EI-BGC-MSsplash10-02t9-7900000000-bf1beeca5227a276a1a9
Predicted MS/MS Spectrum - 10V, Positive (Annotated)Predicted LC-MS/MSNot Available
Predicted MS/MS Spectrum - 20V, Positive (Annotated)Predicted LC-MS/MSNot Available
Predicted MS/MS Spectrum - 40V, Positive (Annotated)Predicted LC-MS/MSNot Available
Predicted MS/MS Spectrum - 10V, Negative (Annotated)Predicted LC-MS/MSNot Available
Predicted MS/MS Spectrum - 20V, Negative (Annotated)Predicted LC-MS/MSNot Available
Predicted MS/MS Spectrum - 40V, Negative (Annotated)Predicted LC-MS/MSNot Available
LC-MS/MS Spectrum - LC-ESI-qTof , PositiveLC-MS/MSNot Available
LC-MS/MS Spectrum - LC-ESI-QQ , negativeLC-MS/MSsplash10-014i-0900000000-5049b81b3f21c5158973
LC-MS/MS Spectrum - LC-ESI-QQ , negativeLC-MS/MSsplash10-014i-0900000000-c7ee77e191a097d4e0ba
LC-MS/MS Spectrum - LC-ESI-QQ , negativeLC-MS/MSsplash10-00lr-0900000000-004a71f655e522e841de
LC-MS/MS Spectrum - LC-ESI-QQ , negativeLC-MS/MSsplash10-001i-4900000000-b7b03cbc9d434e2b03f2
LC-MS/MS Spectrum - LC-ESI-QQ , negativeLC-MS/MSsplash10-003i-9100000000-8a0cf328f650c7cd4780
MS/MS Spectrum - , positiveLC-MS/MSsplash10-00di-0900000000-60a947f3a3a65702c43b

Targets

Kind
Protein
Organism
Humans
Pharmacological action
Yes
General Function
Voltage-gated potassium channel activity
Specific Function
Potassium channel activated by both membrane depolarization or increase in cytosolic Ca(2+) that mediates export of K(+). It is also activated by the concentration of cytosolic Mg(2+). Its activati...
Gene Name
KCNMA1
Uniprot ID
Q12791
Uniprot Name
Calcium-activated potassium channel subunit alpha-1
Molecular Weight
137558.115 Da
References
  1. Dong DL, Luan Y, Feng TM, Fan CL, Yue P, Sun ZJ, Gu RM, Yang BF: Chlorzoxazone inhibits contraction of rat thoracic aorta. Eur J Pharmacol. 2006 Sep 18;545(2-3):161-6. Epub 2006 Jun 29. [PubMed:16859676]
  2. Alvina K, Khodakhah K: KCa channels as therapeutic targets in episodic ataxia type-2. J Neurosci. 2010 May 26;30(21):7249-57. doi: 10.1523/JNEUROSCI.6341-09.2010. [PubMed:20505091]
  3. Syme CA, Gerlach AC, Singh AK, Devor DC: Pharmacological activation of cloned intermediate- and small-conductance Ca(2+)-activated K(+) channels. Am J Physiol Cell Physiol. 2000 Mar;278(3):C570-81. [PubMed:10712246]

Enzymes

Kind
Protein
Organism
Humans
Pharmacological action
Unknown
Actions
Substrate
Inhibitor
General Function
Steroid hydroxylase activity
Specific Function
Metabolizes several precarcinogens, drugs, and solvents to reactive metabolites. Inactivates a number of drugs and xenobiotics and also bioactivates many xenobiotic substrates to their hepatotoxic ...
Gene Name
CYP2E1
Uniprot ID
P05181
Uniprot Name
Cytochrome P450 2E1
Molecular Weight
56848.42 Da
References
  1. Pelkonen O, Maenpaa J, Taavitsainen P, Rautio A, Raunio H: Inhibition and induction of human cytochrome P450 (CYP) enzymes. Xenobiotica. 1998 Dec;28(12):1203-53. [PubMed:9890159]
  2. Kurata N, Nishimura Y, Iwase M, Fischer NE, Tang BK, Inaba T, Yasuhara H: Trimethadione metabolism by human liver cytochrome P450: evidence for the involvement of CYP2E1. Xenobiotica. 1998 Nov;28(11):1041-7. [PubMed:9879636]
  3. Ernstgard L, Warholm M, Johanson G: Robustness of chlorzoxazone as an in vivo measure of cytochrome P450 2E1 activity. Br J Clin Pharmacol. 2004 Aug;58(2):190-200. [PubMed:15255802]
  4. Flockhart Table of Drug Interactions [Link]
Kind
Protein
Organism
Humans
Pharmacological action
Unknown
Actions
Substrate
General Function
Vitamin d 24-hydroxylase activity
Specific Function
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally un...
Gene Name
CYP1A1
Uniprot ID
P04798
Uniprot Name
Cytochrome P450 1A1
Molecular Weight
58164.815 Da
References
  1. Wiercinska P, Squires EJ: Chlorzoxazone metabolism by porcine cytochrome P450 enzymes and the effect of cytochrome b5. Drug Metab Dispos. 2010 May;38(5):857-62. doi: 10.1124/dmd.109.030528. Epub 2010 Feb 17. [PubMed:20164110]
  2. Warrington JS, Court MH, Greenblatt DJ, von Moltke LL: Phenacetin and chlorzoxazone biotransformation in aging male Fischer 344 rats. J Pharm Pharmacol. 2004 Jun;56(6):819-25. [PubMed:15231049]
Kind
Protein
Organism
Humans
Pharmacological action
Unknown
Actions
Substrate
General Function
Oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen
Specific Function
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally un...
Gene Name
CYP1A2
Uniprot ID
P05177
Uniprot Name
Cytochrome P450 1A2
Molecular Weight
58293.76 Da
References
  1. Yang TJ, Sai Y, Krausz KW, Gonzalez FJ, Gelboin HV: Inhibitory monoclonal antibodies to human cytochrome P450 1A2: analysis of phenacetin O-deethylation in human liver. Pharmacogenetics. 1998 Oct;8(5):375-82. [PubMed:9825829]
  2. Ono S, Hatanaka T, Hotta H, Tsutsui M, Satoh T, Gonzalez FJ: Chlorzoxazone is metabolized by human CYP1A2 as well as by human CYP2E1. Pharmacogenetics. 1995 Jun;5(3):143-50. [PubMed:7550365]
Kind
Protein
Organism
Humans
Pharmacological action
Unknown
Actions
Substrate
General Function
Steroid hydroxylase activity
Specific Function
Exhibits a high coumarin 7-hydroxylase activity. Can act in the hydroxylation of the anti-cancer drugs cyclophosphamide and ifosphamide. Competent in the metabolic activation of aflatoxin B1. Const...
Gene Name
CYP2A6
Uniprot ID
P11509
Uniprot Name
Cytochrome P450 2A6
Molecular Weight
56501.005 Da
References
  1. Shimada T, Tsumura F, Yamazaki H: Prediction of human liver microsomal oxidations of 7-ethoxycoumarin and chlorzoxazone with kinetic parameters of recombinant cytochrome P-450 enzymes. Drug Metab Dispos. 1999 Nov;27(11):1274-80. [PubMed:10534312]
  2. Hukkanen J, Jacob Iii P, Peng M, Dempsey D, Benowitz NL: Effects of nicotine on cytochrome P450 2A6 and 2E1 activities. Br J Clin Pharmacol. 2010 Feb;69(2):152-9. doi: 10.1111/j.1365-2125.2009.03568.x. [PubMed:20233178]
  3. Soucek P: Expression of cytochrome P450 2A6 in Escherichia coli: purification, spectral and catalytic characterization, and preparation of polyclonal antibodies. Arch Biochem Biophys. 1999 Oct 15;370(2):190-200. doi: 10.1006/abbi.1999.1388. [PubMed:10510277]
Kind
Protein
Organism
Humans
Pharmacological action
Unknown
Actions
Substrate
Inhibitor
Curator comments
The FDA document attached suggests that this drug is a weak CYP3A inhibitor.
General Function
Vitamin d3 25-hydroxylase activity
Specific Function
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It performs a variety of oxidation react...
Gene Name
CYP3A4
Uniprot ID
P08684
Uniprot Name
Cytochrome P450 3A4
Molecular Weight
57342.67 Da
References
  1. Gorski JC, Jones DR, Wrighton SA, Hall SD: Contribution of human CYP3A subfamily members to the 6-hydroxylation of chlorzoxazone. Xenobiotica. 1997 Mar;27(3):243-56. [PubMed:9141232]
  2. Wiercinska P, Squires EJ: Chlorzoxazone metabolism by porcine cytochrome P450 enzymes and the effect of cytochrome b5. Drug Metab Dispos. 2010 May;38(5):857-62. doi: 10.1124/dmd.109.030528. Epub 2010 Feb 17. [PubMed:20164110]
  3. Gurley BJ, Gardner SF, Hubbard MA, Williams DK, Gentry WB, Cui Y, Ang CY: Cytochrome P450 phenotypic ratios for predicting herb-drug interactions in humans. Clin Pharmacol Ther. 2002 Sep;72(3):276-87. doi: 10.1067/mcp.2002.126913. [PubMed:12235448]
  4. FDA Drug Development and Drug Interactions: Table of Substrates, Inhibitors and Inducers [Link]
Kind
Protein
Organism
Humans
Pharmacological action
Unknown
Actions
Substrate
General Function
Steroid hydroxylase activity
Specific Function
Responsible for the metabolism of many drugs and environmental chemicals that it oxidizes. It is involved in the metabolism of drugs such as antiarrhythmics, adrenoceptor antagonists, and tricyclic...
Gene Name
CYP2D6
Uniprot ID
P10635
Uniprot Name
Cytochrome P450 2D6
Molecular Weight
55768.94 Da
References
  1. Shimada T, Tsumura F, Yamazaki H: Prediction of human liver microsomal oxidations of 7-ethoxycoumarin and chlorzoxazone with kinetic parameters of recombinant cytochrome P-450 enzymes. Drug Metab Dispos. 1999 Nov;27(11):1274-80. [PubMed:10534312]
  2. Gorski JC, Jones DR, Wrighton SA, Hall SD: Contribution of human CYP3A subfamily members to the 6-hydroxylation of chlorzoxazone. Xenobiotica. 1997 Mar;27(3):243-56. [PubMed:9141232]

Drug created on June 13, 2005 07:24 / Updated on October 02, 2020 03:00

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