Chlorzoxazone USP is a centrally acting skeletal muscle relaxant, available as tablets of 500 mg for oral administration.
Chlorzoxazone is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute, painful musculoskeletal conditions. The mode of action of this drug has not been clearly identified, but may be related to its sedative properties. Chlorzoxazone does not directly relax tense skeletal muscles in man.
Media Articles Related to Chlorzoxazone
Muscle Cramps (Charley Horse) and Muscle Spasms: Symptoms, Causes, and Treatments
Source: MedicineNet Muscle Cramps Specialty [2016.06.24]
Title: Muscle Cramps (Charley Horse) and Muscle Spasms: Symptoms, Causes, and Treatments
Created: 6/8/2015 12:00:00 AM
Last Editorial Review: 6/24/2016 12:00:00 AM
Source: MedicineNet Amyotrophic Lateral Sclerosis Specialty [2016.04.21]
Title: Muscle Spasms
Category: Diseases and Conditions
Created: 6/16/2009 12:00:00 AM
Last Editorial Review: 4/21/2016 12:00:00 AM
Published Studies Related to Chlorzoxazone
Effect of high-dose aspirin on CYP2E1 activity in healthy subjects measured using chlorzoxazone as a probe. [2006.01]
The authors evaluated the effect of high-dose aspirin at a therapeutic dose, using chlorzoxazone as a probe for CYP2E1 enzyme activity. In a randomized, open-label, 2-way crossover study, 10 healthy men were treated 3 times daily for 6 days with 1 g aspirin or placebo...
An interaction between the cytochrome P450 probe substrates chlorzoxazone (CYP2E1) and midazolam (CYP3A). [2001.11]
AIMS: The use of multiple probe substrates to evaluate the activity of drug metabolizing enzymes requires that there are no inter-substrate interactions. As part of a series of studies to develop a clinically useful collection of probe substrates that could be given alone or in any combination, we observed an interaction between midazolam (MDZ) and another component of the six-drug cocktail. Published data indicated that the interacting component was likely to be chlorzoxazone. This was investigated as part of a second study. The data relating to the interaction from both studies are reported here... CONCLUSIONS: Chlorzoxazone appears to significantly influence the pharmacokinetics of oral MDZ, probably through inhibition of first pass metabolism by CYP3A in the GI tract. Data from these studies and literature evidence showing a further interaction between chlorzoxazone and CYP1A2 substrates and questions concerning the specificity of chlorzoxazone as a probe substrate for CYP2E1, indicate that the use of chlorzoxazone in multisubstrate probe cocktails should be avoided.
Clinical Trials Related to Chlorzoxazone
The Effect of Chlorzoxazone on Moderate to Severe Postoperative Pain After Spine Surgery [Recruiting]
Placebo-Controlled Cross Over Trial of Chlorzoxazone Intake [Completed]
The overall goals of this study are to (1) expand knowledge about interactions of
chlorzoxazone with alcohol by assessing the effects of chlorzoxazone compared to placebo in
moderate and heavy social alcohol users and (2) to compare the effects of chlorzoxazone on
visual cue induced alcohol craving to placebo in moderate to heavy social alcohol users.
Chlorzoxazone in Hip and Knee Arthroplasty [Not yet recruiting]
The purpose of this study is to elucidate whether patients operated with THA and TKA can
benefit from treatment with chlorzoxazone.
Effect of Ethanol and Genetic Polymorphisms on Bupropion Metabolism [Completed]
The two purposes of this study are
1. to determine what effect the chronic and moderate/heavy drinking of alcoholic beverages
1. on the blood level of bupropion and chlorzoxazone and their major breakdown
products in the blood and
2. on the stimulant effect of bupropion and
2. to determine what effect a normal and common (25% frequency) genetic variation of a
specific liver enzyme (that breaks down bupropion) has
1. on the blood levels of bupropion and its major breakdown products in the blood and
2. on the stimulant effect of bupropion.
Two groups of volunteers will be recruited for this study:
1. volunteers who drink moderate to heavy amounts of alcohol frequently and
2. volunteers who usually do not drink alcohol.
Volunteers will NOT be asked to change their drinking (or nondrinking) habits during the
Pharmacokinetic Study to Investigate Low-dose Combinations of a Cocktail of Seven Drugs for Simultaneous Phenotyping of Cytochromes [Completed]
The purpose of this study is to assess whether a cocktail of seven approved drugs (so-called
"Basel cocktail") can be used for simultaneous phenotyping of CYP1A2, CYP2B6, CYP2C9,
CYP2C19, CYP2D6, CYP2E1 and CYP3A4.
Reports of Suspected Chlorzoxazone Side Effects
Completed Suicide (12),
Toxicity TO Various Agents (2),
Hepatic Enzyme Increased (2),
Feeling Abnormal (2),
Confusional State (1),
Drug Ineffective (1),
Abdominal Pain Upper (1), more >>