Chlorzoxazone

Chlorzoxazone
Clinical data
Trade names	Parafonforte
AHFS/Drugs.com	Monograph
MedlinePlus	a682577
Routes of; administration	oral
ATC code	M03BB03 (WHO) ;
Pharmacokinetic data
Bioavailability	well absorbed
Protein binding	13–18%
Metabolism	hepatic
Elimination half-life	1.1 hr Duration of action 3-4 hrs.
Excretion	urine (<1%)
Identifiers
	IUPAC name 5-chloro-3H-benzooxazol-2-one;
CAS Number	95-25-0 ;
PubChem CID	2733;
IUPHAR/BPS	2322;
DrugBank	DB00356 ;
ChemSpider	2632 ;
UNII	H0DE420U8G;
KEGG	D00771 ;
ChEBI	CHEBI:3655 ;
ChEMBL	ChEMBL1371 ;
CompTox Dashboard (EPA)	DTXSID9022813 ;
ECHA InfoCard	100.002.186
Chemical and physical data
Formula	C7H4ClNO2
Molar mass	169.56 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES Clc2cc1c(OC(=O)N1)cc2;
	InChI InChI=1S/C7H4ClNO2/c8-4-1-2-6-5(3-4)9-7(10)11-6/h1-3H,(H,9,10) ; Key:TZFWDZFKRBELIQ-UHFFFAOYSA-N ;
	(verify)

Chlorzoxazone (INN) is a centrally acting muscle relaxant used to treat muscle spasm and the resulting pain or discomfort. It acts on the spinal cord by depressing reflexes. It is sold under the trade names "'Lorzone'", Paraflex and Muscol and in combination form as Parafon Forte, a combination of chlorzoxazone and acetaminophen (paracetamol). Possible side effects include dizziness, lightheadedness, malaise, nausea, vomiting, and liver dysfunction. Used with acetaminophen it has added risk of hepatoxicity,^{[medical citation needed]}. It can also be administered for acute pain in general and for tension headache (muscle contraction headache).

Like metaxalone, its mechanism of action is still in question. It is believed that metaxalone works by altering serotonin levels and acting as a mild MAO inhibitor.^{[medical citation needed]} The mechanism of action of chlorzoaxazone is thought^{[by whom?]} to act on Gaba-A & B receptors and voltage-gated calcium channels to a degree.^{[medical citation needed]} General central nervous system depression is the only currently accepted aspect to its medical benefits.^{[medical citation needed]} Elucidation of the exact mechanism of action is ongoing but there is limited study due to the existence of more effective, safe muscle relaxants (ex. diazepam, cyclobenzaprine, tizanidine), greatly limiting the potential benefit of identifying novel compounds which share chlorzoxazone's mechanism of action.

References

^[1]

^ Chloroxazone Safety Data Sheet

D.F. Marsh, U.S. patent 2,895,877 (1959).
Dong DL, Luan Y, Feng TM, Fan CL, Yue P, Sun ZJ, Gu RM, Yang BF (2006). "Chlorzoxazone inhibit contraction of rat thoracic aorta". Eur J Pharmacol. 545 (2–3): 161–6. doi:10.1016/j.ejphar.2006.06.063. PMID 16859676.
Park J, Kim K, Park P, Ha J (2006). "Effect of high-dose aspirin on CYP2E1 activity in healthy subjects measured using chlorzoxazone as a probe". J Clin Pharmacol. 46 (1): 109–14. doi:10.1177/0091270005282635. PMID 16397290.
Wan J, Ernstgård L, Song B, Shoaf S (2006). "Chlorzoxazone metabolism is increased in fasted Sprague-Dawley rats". J Pharm Pharmacol. 58 (1): 51–61. doi:10.1211/jpp.58.1.0007. PMC 1388188. PMID 16393464.
PARAFON DSC (chlorzoxazone) tablet, Daily Med, U.S. National Library of Medicine

This drug article relating to the musculoskeletal system is a stub. You can help Wikipedia by expanding it.

[1] Chloroxazone Safety Data Sheet

[1]

See also

References