Chlorzoxazone
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| Systematic (IUPAC) name | |
|---|---|
|
5-chloro-3H-benzooxazol-2-one | |
| Clinical data | |
| Trade names | Parafonforte |
| AHFS/Drugs.com | monograph |
| MedlinePlus | a682577 |
| Routes of administration | oral |
| Pharmacokinetic data | |
| Bioavailability | well absorbed |
| Protein binding | 13–18% |
| Metabolism | hepatic |
| Biological half-life | 1.1 hr |
| Excretion | urine (<1%) |
| Identifiers | |
| CAS Number |
95-25-0  |
| ATC code | M03BB03 |
| PubChem | CID 2733 |
| IUPHAR/BPS | 2322 |
| DrugBank |
DB00356 |
| ChemSpider |
2632 |
| UNII |
H0DE420U8G |
| KEGG |
D00771 |
| ChEBI |
CHEBI:3655 |
| ChEMBL |
CHEMBL1371 |
| Chemical data | |
| Formula | C7H4ClNO2 |
| Molar mass | 169.565 g/mol |
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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 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, which is why the combination is not recommended. It can also be administered for acute pain in general and for tension headache (muscle contraction headache).
Synthesis
Chlorzoxazone, 5-chloro-2-benzoxazolione, is synthesized by a hetercyclization reaction of 2-amino-4-chlorophenol with phosgene.
References
- 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
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