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Chlorzoxazone


Chlorzoxazone
Systematic (IUPAC) name
5-chloro-3H-benzooxazol-2-one
Identifiers
CAS number	95-25-0
ATC code	M03BB03
PubChem	2733
DrugBank	APRD00308
Chemical data
Formula	C₇H₄Cl N O₂
Mol. mass	169.565 g/mol
Pharmacokinetic data
Bioavailability	well absorbed
Protein binding	13–18%
Metabolism	hepatic
Half life	1.1 hr
Excretion	urine (<1%)
Therapeutic considerations
Pregnancy cat.	?
Legal status
Routes	oral

Chlorzoxazone 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 as Parafon Forte, a combination of chlorzoxazone and acetaminophen. Possible side effects include dizziness, lightheadedness, malaise, nausea, vomiting, and liver dysfunction.

v • d • e Muscle relaxants (M03)
Peripherally acting (primarily antinicotinic, neuromuscular-blocking drugs)	curare alkaloids (Alcuronium, Dimethyltubocurarine, Tubocurarine) - choline derivatives (Suxamethonium) - other quaternary ammonium compounds (Atracurium, Cisatracurium, Doxacurium chloride, Fazadinium bromide, Gallamine, Hexafluronium, Mivacurium chloride, Pancuronium, Pipecuronium bromide, Rocuronium bromide, Vecuronium) - other (Botulinum toxin)
Centrally acting	carbamic acid esters (Phenprobamate, Carisoprodol, Methocarbamol, Styramate, Febarbamate), Baclofen, Chlormezanone, Chlorzoxazone, Cyclobenzaprine, Lorazepam, Mephenesin, Orphenadrine, Phenyramidol, Pridinol, Tetrazepam, Thiocolchicoside, Tizanidine, Tolperisone
Directly acting	Dantrolene