Description

Simple

A medication that relieves stiffness caused by muscle strain that is often combined with physical therapy or painkillers for maximum effect.

Clinical

A drug with muscle relaxant properties that is used as an adjunct to physical therapy and analgesics to treat stiffness and pain caused by a variety of musculoskeletal conditions.

Overview

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)

Pharmacology

Indication

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

Pharmacodynamic

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. in... Read more

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... Read more

Absorption

Information currently not available.

Protein binding

13-18%

Volume of distribution

Information currently not available.

Clearance

Information currently not available.

Half life

Information currently not available.

Route of elimination

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

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.

Adverse Effects

Contraindications

  • Regions: US
  • Patient Conditions:
      • Name: Drug intolerance
      • Drugbank Id: DBCOND0012019

Food Interactions

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

Interactions

Type in a drug name to check for interaction with Chlorzoxazone
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  • Paracetamol(acetaminophen)
  • Paxil(paroxetine)
  • Pamelor(nortriptyline)
  • Panadol(acetaminophen)
  • Patanol(olopatadine ophthalmic)
  • Pataday(olopatadine ophthalmic)
  • Parnate(tranylcypromine)
  • Pazeo(olopatadine ophthalmic)
(R)-warfarin
The metabolism of (R)-warfarin can be decreased when combined with Chlorzoxazone.
1-(2-Phenylethyl)-4-phenyl-4-acetoxypiperidine
The metabolism of Chlorzoxazone can be decreased when combined with 1-(2-Phenylethyl)-4-phenyl-4-acetoxypiperidine.
2,5-Dimethoxy-4-ethylthioamphetamine
The risk or severity of adverse effects can be increased when Chlorzoxazone is combined with 2,5-Dimethoxy-4-ethylthioamphetamine.
4-Bromo-2,5-dimethoxyamphetamine
The risk or severity of adverse effects can be increased when Chlorzoxazone is combined with 4-Bromo-2,5-dimethoxyamphetamine.
4-Methoxyamphetamine
The risk or severity of adverse effects can be increased when Chlorzoxazone is combined with 4-Methoxyamphetamine.
5-methoxy-N,N-dimethyltryptamine
The risk or severity of adverse effects can be increased when Chlorzoxazone is combined with 5-methoxy-N,N-dimethyltryptamine.
6-O-benzylguanine
The metabolism of 6-O-benzylguanine can be decreased when combined with Chlorzoxazone.
7-Nitroindazole
The risk or severity of adverse effects can be increased when Chlorzoxazone is combined with 7-Nitroindazole.
7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline
The risk or severity of adverse effects can be increased when Chlorzoxazone is combined with 7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline.
8-azaguanine
The metabolism of 8-azaguanine can be decreased when combined with Chlorzoxazone.
8-chlorotheophylline
The metabolism of 8-chlorotheophylline can be decreased when combined with Chlorzoxazone.
9-Deazaguanine
The metabolism of 9-Deazaguanine can be decreased when combined with Chlorzoxazone.
9-Methylguanine
The metabolism of 9-Methylguanine can be decreased when combined with Chlorzoxazone.
Abacavir
Chlorzoxazone may decrease the excretion rate of Abacavir which could result in a higher serum level.
Abatacept
The metabolism of Chlorzoxazone can be increased when combined with Abatacept.
Abiraterone
The serum concentration of Chlorzoxazone can be increased when it is combined with Abiraterone.
Acarbose
Acarbose may decrease the excretion rate of Chlorzoxazone which could result in a higher serum level.
Acebutolol
The metabolism of Chlorzoxazone can be decreased when combined with Acebutolol.
Aceclofenac
Aceclofenac may decrease the excretion rate of Chlorzoxazone which could result in a higher serum level.
Acefylline
The metabolism of Acefylline can be decreased when combined with Chlorzoxazone.
3 References
  1. 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. 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. 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