CLINICAL TRIALS PROFILE FOR FLEXERIL

All Clinical Trials for FLEXERIL

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00246389 ↗	An Effectiveness and Safety Study of Cyclobenzaprine HCl Alone or in Combination With Ibuprofen for Acute Back or Neck Muscle Pain With Muscle Spasm	Completed	McNeil Consumer & Specialty Pharmaceuticals, a Division of McNeil-PPC, Inc.	Phase 4	1969-12-31	The purpose of this study is to evaluate the effectiveness and safety of cyclobenzaprine HCl 5 mg (muscle spasm medication) taken three times a day, alone or in combination with ibuprofen 400 mg or 800 mg (pain relief medication) taken three times a day, for the treatment of back or neck muscle pain with muscle spasm.
NCT00610610 ↗	Paroxetine-CR (Paxil-CR) in the Treatment of Patients With Fibromyalgia Syndrome	Completed	GlaxoSmithKline	Phase 4	2002-01-01	Objective: Although there is a high comorbidity of depressive and/or anxiety disorders with fibromyalgia, information on the clinical implications of this comorbidity is limited. We investigated whether a history of depressive and/or anxiety disorders was associated with response to treatment in a double blind, randomized, placebo controlled trial of paroxetine controlled release (CR) in fibromyalgia. Method: One hundred and sixteen fibromyalgia subjects were randomized to receive paroxetine CR (dose 12.5-62.5 mg/day) or placebo for 12 weeks. The Mini International Neuropsychiatric Interview (M.I.N.I-plus) was used to ascertain current or past diagnoses of depressive and anxiety disorders. Patients with current depressive or anxiety disorders were excluded, but those with past diagnoses were enrolled in the trial. Subjective depression and anxiety were assessed using the Beck Depression Inventory (BDI) and the Beck Anxiety Inventory (BAI); subjects were excluded if they scored greater than 23 on the BDI. Health Status was determined using the 36-Item Short Form Health Survey (SF-36), the Sheehan Disability Scale (SDS), the Perceived Stress Scale (PSS) and the Pittsburgh Sleep Quality Index (PSQI). The primary outcome was treatment response defined as ≥ 25% reduction in the Fibromyalgia Impact Questionnaire (FIQ) score. Secondary outcomes included changes in scores on the Clinical Global Impression-Severity and Improvement (CGI-S and CGI-I respectively), the Visual Analogue Scale for Pain (VAS) scores and number of tender points.
NCT00610610 ↗	Paroxetine-CR (Paxil-CR) in the Treatment of Patients With Fibromyalgia Syndrome	Completed	Duke University	Phase 4	2002-01-01	Objective: Although there is a high comorbidity of depressive and/or anxiety disorders with fibromyalgia, information on the clinical implications of this comorbidity is limited. We investigated whether a history of depressive and/or anxiety disorders was associated with response to treatment in a double blind, randomized, placebo controlled trial of paroxetine controlled release (CR) in fibromyalgia. Method: One hundred and sixteen fibromyalgia subjects were randomized to receive paroxetine CR (dose 12.5-62.5 mg/day) or placebo for 12 weeks. The Mini International Neuropsychiatric Interview (M.I.N.I-plus) was used to ascertain current or past diagnoses of depressive and anxiety disorders. Patients with current depressive or anxiety disorders were excluded, but those with past diagnoses were enrolled in the trial. Subjective depression and anxiety were assessed using the Beck Depression Inventory (BDI) and the Beck Anxiety Inventory (BAI); subjects were excluded if they scored greater than 23 on the BDI. Health Status was determined using the 36-Item Short Form Health Survey (SF-36), the Sheehan Disability Scale (SDS), the Perceived Stress Scale (PSS) and the Pittsburgh Sleep Quality Index (PSQI). The primary outcome was treatment response defined as ≥ 25% reduction in the Fibromyalgia Impact Questionnaire (FIQ) score. Secondary outcomes included changes in scores on the Clinical Global Impression-Severity and Improvement (CGI-S and CGI-I respectively), the Visual Analogue Scale for Pain (VAS) scores and number of tender points.
NCT00778037 ↗	Bioequivalence Study of Cyclobenzaprine Hydrochloride 10 mg Tablets, USP Under Fasting Conditions	Completed	Ranbaxy Laboratories Limited	N/A	2006-09-01	To compare the single-dose oral bioavailability of Cyclobenzaprine hydrochloride 10 mg tablet of Ohm Labs Inc (A subsidiary of Ranbaxy Pharmaceuticals Inc USA.) with Flexeril® 10 mg tablet (containing Cyclobenzaprine hydrochloride 10 mg) of McNeil Consumer & Specialty Pharmaceuticals, in healthy, adult, male, human subjects under fasting condition.
NCT00790270 ↗	Comparison of Ibuprofen, Cyclobenzaprine, or Both for Acute Cervical Strain: A Randomized Clinical Trial	Completed	Stony Brook University	Phase 2	2003-01-01	The purpose of this study is to see whether the combination of a muscle relaxant and anti-inflammatory drug is more effective at relieving pain in patients with neck strains or whiplash than either of the two medications alone.
NCT01028014 ↗	Medication Effects on Periurethral Sensation,Urethral Sphincter Activity and Pressure Flow Parameters	Completed	Astellas Pharma Inc	N/A	2010-04-01	Lower urinary tract symptoms such as urinary leakage and overactive bladder affect millions of American women. Women may develop these problems because the innervation of the muscles of the bladder and urethra are injured. Most research on treating these problems has focused on the abnormalities of the bladder muscle, but newer studies have shown abnormalities in the innervation and muscle function of the urethra. Women with these symptoms may benefit from treatment with medications to improve their urethral function. However, to truly understand what types of medications will help women with these symptoms, the investigators wish to study how these medications affect innervation and muscle function in healthy women who do not have lower urinary tract symptoms.

Clinical Trial Conditions for FLEXERIL

Condition Name

Condition Name for FLEXERIL
Intervention	Trials
Pain	2
Healthy	1
Pain, Postoperative	1
Postoperative Pain	1

Condition MeSH

Condition MeSH for FLEXERIL
Intervention	Trials
Pain, Postoperative	2
Spasm	1
Head and Neck Neoplasms	1
Myotonia	1

Clinical Trial Locations for FLEXERIL

Trials by Country

Trials by Country for FLEXERIL
Location	Trials
United States	9
India	1

Trials by US State

Trials by US State for FLEXERIL
Location	Trials
Georgia	2
California	1
Michigan	1
Illinois	1
Alabama	1

Clinical Trial Progress for FLEXERIL

Clinical Trial Phase

Clinical Trial Phase for FLEXERIL
Clinical Trial Phase	Trials
Phase 4	3
Phase 2	2
Phase 1	1

Clinical Trial Status

Clinical Trial Status for FLEXERIL
Clinical Trial Phase	Trials
Completed	7
Withdrawn	1
Terminated	1

Clinical Trial Sponsors for FLEXERIL

Sponsor Name

Sponsor Name for FLEXERIL
Sponsor	Trials
Stony Brook University	1
Astellas Pharma Inc	1
University of Alabama at Birmingham	1

Sponsor Type

Sponsor Type for FLEXERIL
Sponsor	Trials
Other	8
Industry	6

Summary
FLEXERIL (cyclobenzaprine) remains primarily a centrally acting muscle relaxant used for short-term relief of muscle spasms associated with acute musculoskeletal conditions. Its market persists with limited new clinical trial activity; existing data focus on its efficacy and safety. Market projections indicate a gradual decline in growth driven by generics and newer alternatives.

Clinical Trials Update

• No recent large-scale, indication-specific clinical trials for FLEXERIL have been registered in ClinicalTrials.gov since 2020.
• Most studies focus on its comparative efficacy against other muscle relaxants or combination therapies for acute low back pain.
• Ongoing research emphasizes safety profiles when combined with other CNS depressants but does not involve new formulations or extended-release variants.
• The drug retains FDA approval since 1977, primarily for short-term use; no recent FDA updates or indication expansions are reported.

Market Analysis

Current Market Size

• The global muscle relaxant market was valued at approximately $2.6 billion in 2022, projected to grow at a CAGR of around 3.5% until 2030 ([1]).
• FLEXERIL accounts for roughly 65% of the US muscle relaxant prescription volume, with over 10 million prescriptions annually in the US alone ([2]).

Patent & Regulatory Status

• FLEXERIL's patent protection expired in 2003.
• Its market is dominated by generic versions, reducing its price point and profit margins.
• No recent FDA approvals for new formulations or indications.

Competitive Landscape

• Key competitors include tizanidine, methocarbamol, and carisoprodol.
• The shift toward drugs with fewer sedative effects impacts FLEXERIL's market share.
• Newer therapies, such as botulinum toxins and multimodal pain management drugs, encroach on the muscle relaxant segment.

Market Drivers & Constraints

• Unmet needs for long-term muscle spasm management limit current drug utilization.
• Concerns over sedative side effects and dependency limit prescription volume.
• Insurance coverage biases favor newer, possibly branded drugs with perceived safety advantages.

Market Projection

• The market for FLEXERIL is expected to decline by an average of 1-2% annually over the next five years due to generic penetration and alternative therapies.
• Growth in niche markets, such as chronic spasm management or combination therapies, remains limited but may offer modest opportunities.
• Overall, the US market volume for FLEXERIL prescriptions will likely decrease, with total sales declining correspondingly, unless a new indication or formulation is introduced.

Key Takeaways

• No recent clinical trials suggest new therapeutic uses or formulations for FLEXERIL.
• The market declines driven by patent expiry, competition, and evolving prescriber preferences.
• Generic availability suppresses pricing power, constraining revenue growth.
• Future prospects depend heavily on repositioning or extending indications; none are currently under active clinical development.

Frequently Asked Questions (FAQs)

Last updated: February 4, 2026

1. Are there any ongoing clinical trials for FLEXERIL?
   No significant recent trials focus on new indications or formulations; most concern comparative efficacy or safety in combination therapies.

2. What is the main competition for FLEXERIL?
   Tizanidine, methocarbamol, and carisopram are primary competitors, alongside newer options with fewer side effects.

3. Can FLEXERIL be used beyond short-term treatment?
   FDA approval restricts use to short-term management of muscle spasms; off-label long-term use lacks evidence and carries safety concerns.

4. Are there any patents or exclusivity rights for FLEXERIL?
   The original patent expired in 2003; current formulations are off patent, mainly produced as generics.

5. What future market trends could impact FLEXERIL?
   Development of compounds with improved safety profiles, inclusion in multimodal pain management, or expanded indications could influence its market position.

Sources

1. MarketWatch, "Global Muscle Relaxant Market Size & Trends," 2022.
2. IQVIA, Prescription Data, 2022.