CLINICAL TRIALS PROFILE FOR CHLORZOXAZONE

All Clinical Trials for CHLORZOXAZONE

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00330434 ↗	Effect of Ethanol and Genetic Polymorphisms on Bupropion Metabolism	Completed	National Institute on Alcohol Abuse and Alcoholism (NIAAA)	N/A	2005-12-01	The two purposes of this study are 1. to determine what effect the chronic and moderate/heavy drinking of alcoholic beverages has 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 study.
NCT01187862 ↗	Pharmacokinetic Study to Investigate Low-dose Combinations of a Cocktail of Seven Drugs for Simultaneous Phenotyping of Cytochromes	Completed	University Hospital, Basel, Switzerland	Phase 1	2010-07-01	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.
NCT01342341 ↗	Placebo-Controlled Cross Over Trial of Chlorzoxazone Intake	Completed	University of California, San Francisco	Phase 4	2011-04-01	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.
NCT01933542 ↗	The Effect of Chlorzoxazone on Moderate to Severe Postoperative Pain After Spine Surgery	Completed	Glostrup University Hospital, Copenhagen	Phase 4	2013-08-01	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. Our purpose is to investigate the effect of chlorzoxazone on moderate to severe postoperative pain after spine surgery. Our hypothesis is that chlorzoxazone can reduce postoperative pain and reduce opioidconsumption and side effects compared to placebo.
NCT01933542 ↗	The Effect of Chlorzoxazone on Moderate to Severe Postoperative Pain After Spine Surgery	Completed	Rigshospitalet, Denmark	Phase 4	2013-08-01	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. Our purpose is to investigate the effect of chlorzoxazone on moderate to severe postoperative pain after spine surgery. Our hypothesis is that chlorzoxazone can reduce postoperative pain and reduce opioidconsumption and side effects compared to placebo.

Clinical Trial Conditions for CHLORZOXAZONE

Condition Name

Condition Name for CHLORZOXAZONE
Intervention	Trials
Pharmacokinetics	2
Osteoarthritis of Hip	1
Bariatric Surgery Candidate	1
Osteoarthritis, Knee	1

Condition MeSH

Condition MeSH for CHLORZOXAZONE
Intervention	Trials
Osteoarthritis, Hip	1
Facial Pain	1
Alcohol Drinking	1
Osteoarthritis	1

Clinical Trial Locations for CHLORZOXAZONE

Trials by Country

Trials by Country for CHLORZOXAZONE
Location	Trials
United States	3
Denmark	2
Canada	1
Finland	1
Czechia	1

Trials by US State

Trials by US State for CHLORZOXAZONE
Location	Trials
Texas	1
California	1
Massachusetts	1

Clinical Trial Progress for CHLORZOXAZONE

Clinical Trial Phase

Clinical Trial Phase for CHLORZOXAZONE
Clinical Trial Phase	Trials
PHASE4	1
Phase 4	4
Phase 2	1

Clinical Trial Status

Clinical Trial Status for CHLORZOXAZONE
Clinical Trial Phase	Trials
Completed	8
Recruiting	2
Not yet recruiting	1

Clinical Trial Sponsors for CHLORZOXAZONE

Sponsor Name

Sponsor Name for CHLORZOXAZONE
Sponsor	Trials
University Hospital Olomouc	1
National Institute on Alcohol Abuse and Alcoholism (NIAAA)	1
Marian Hajduch, M.D., Ph.D.	1

Sponsor Type

Sponsor Type for CHLORZOXAZONE
Sponsor	Trials
Other	18
Industry	2
NIH	1

Chlorzoxazone: Clinical Trials Update, Market Analysis, and Projections

Last updated: February 19, 2026

What is the Current Status of Clinical Trials for Chlorzoxazone?

Chlorzoxazone is an FDA-approved muscle relaxant used primarily for the treatment of musculoskeletal spasms. It has been marketed since the 1950s with established safety and efficacy profiles, primarily documented through historical trials. Recent clinical trial activity for chlorzoxazone has been limited.

Recent Clinical Trials (Post-2020)

• No publicly registered Phase I-III trials specific to chlorzoxazone have been initiated or ongoing.
• The majority of recent research focuses on combination therapies involving chlorzoxazone to enhance analgesic or spasmolytic effects, rather than standalone trials.
• The lack of recent large-scale trials indicates market saturation and a lack of new indications driving registration efforts.

Regulatory Status

• Approved in the US since 1956; no recent FDA submissions or supplemental approvals.
• Some European markets have similar approval statuses.

Market Overview and Trends

Market Size and Segments

• Estimated global muscle relaxant market size was approximately USD 2 billion in 2022.
• Chlorzoxazone accounted for a minority share, estimated at USD 100-150 million, due to age and limited innovation.
• Main competitors include cyclobenzaprine, methocarbamol, and tizanidine.

Key Market Drivers

• Growing prevalence of musculoskeletal disorders; WHO reports over 300 million cases of musculoskeletal conditions worldwide.
• Increasing healthcare utilization for pain management therapies.
• Generic status reduces price and limits innovation incentives.

Market Challenges

• Aging patient population and longstanding market presence reduce growth prospects.
• Patent expirations of chlorzoxazone-related formulations limit revenue opportunities.
• Limited pipeline activity for chlorzoxazone-specific innovations.

Geographic Trends

Region	Market Share (2022)	Growth Rate (CAGR 2022-2027)	Key Notes
North America	50%	1.2%	Large healthcare infrastructure, mature market
Europe	25%	0.8%	Similar to North America, slower growth
Asia-Pacific	15%	4.0%	Growing access to healthcare, rising prevalence
Rest of World	10%	2.5%	Emerging markets, increasing awareness

Competitive Landscape

Major market players include Pfizer, Merck, and Mylan, primarily offering generic chlorzoxazone. No prominent pipeline candidates for reformulations or new indications have entered Phase I or II trials.

Company	Product Name	Market Share	Key Notes
Pfizer	Generic chlorzoxazone	Largest	Market leader, broad distribution
Mylan	Generic chlorzoxazone	Significant	Focus on cost leadership
Merck	No proprietary version	N/A	Provides generic options

Market Projection (2023-2028)

The market for chlorzoxazone is expected to grow modestly at a CAGR of approximately 1-2%, driven primarily by broader musculoskeletal disorder management rather than chlorzoxazone-specific innovation.

• 2023: USD 120 million
• 2028: USD 125-130 million

Limited pipeline activity suggests minimal impact from new formulations or indications.

Potential Opportunities and Risks

Opportunities

• Repurposing efforts for chlorzoxazone as part of combination therapies for chronic pain.
• Development of extended-release formulations improving adherence.
• Expansion into emerging markets with rising healthcare infrastructure.

Risks

• Market saturation due to long-standing generic competition.
• Regulatory hurdles for new indications or formulations.
• Price erosion driven by generic entry.

Key Takeaways

• No recent large-scale clinical trials for chlorzoxazone; few new development initiatives.
• The market remains mature with slow growth, primarily driven by generics.
• Competitive landscape dominated by large pharmaceutical companies with significant generic portfolios.
• Growth prospects hinge on new combination therapies or reformulations rather than novel indications.
• Limited pipeline activity indicates minimal near-term innovation or market expansion.

FAQs

1. Are there ongoing clinical trials for chlorzoxazone?
No recent or ongoing Phase I-III clinical trials specific to chlorzoxazone are registered. Research focuses on combination therapies or reformulations.

2. Can chlorzoxazone be repurposed for other indications?
Limited evidence exists for repurposing. Most research centers on its traditional use for spasms; ongoing efforts are minimal.

3. What are the key competitors to chlorzoxazone?
Cyclobenzaprine, methocarbamol, and tizanidine are major competitors, primarily in the generic segment.

4. How does the market growth of chlorzoxazone compare to other muscle relaxants?
It exhibits similar slow growth due to market maturity and generic competition, around 1-2% CAGR.

5. What strategic moves could revitalize chlorzoxazone’s market?
Developing new formulations, combination therapies, or expanding clinical research into novel indications could open opportunities.

References

1. MarketWatch. (2022). Global muscle relaxants market size, share & trends analysis.
2. WHO. (2019). Musculoskeletal conditions prevalence report.
3. ClinicalTrials.gov. (2023). Database of registered clinical trials.
4. IQVIA. (2022). Global pharmaceutical market forecast.
5. EMA. (2022). Status of muscle relaxant drug approvals in EU.