CLINICAL TRIALS PROFILE FOR FLAGYL

505(b)(2) Clinical Trials for FLAGYL

This table shows clinical trials for potential 505(b)(2) applications. See the next table for all clinical trials

Trial Type	Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
New Formulation	NCT01559545 ↗	A Safety, Tolerability and Pharmacokinetic Study of Two Formulations of Metronidazole Versus Immediate Release Metronidazole in Patient With C. Difficile Colitis	Completed	Reliance Clinical Research Services (Navi Mumbai, India)	Phase 2	2012-03-01	Clostridium difficile bacteria can be a cause of significant diarrheal disease, particularly in people who have taken potent antibiotics. When C. difficile multiplies within the colon, it produces two toxins that cause inflammation and resultant abdominal pain, fever and diarrhea. Current treatment of mild to moderate disease is with immediate release metronidazole, an antibiotic that kills C. difficile. Dr. Reddy's Laboratories has developed a delayed release form of metronidazole to release just before the colon to increase the concentration of antibiotic in the colon to improve the effectiveness of metronidazole treatment and potentially to allow less whole body exposure to the antibiotic. This study will measure the amount of metronidazole in the blood and stool of patients with C. difficile associated diarrhea (CDAD) to confirm that the new formulations are releasing the antibiotic as designed, immediately before the colon.
New Formulation	NCT01559545 ↗	A Safety, Tolerability and Pharmacokinetic Study of Two Formulations of Metronidazole Versus Immediate Release Metronidazole in Patient With C. Difficile Colitis	Completed	Dr. Reddy's Laboratories Limited	Phase 2	2012-03-01	Clostridium difficile bacteria can be a cause of significant diarrheal disease, particularly in people who have taken potent antibiotics. When C. difficile multiplies within the colon, it produces two toxins that cause inflammation and resultant abdominal pain, fever and diarrhea. Current treatment of mild to moderate disease is with immediate release metronidazole, an antibiotic that kills C. difficile. Dr. Reddy's Laboratories has developed a delayed release form of metronidazole to release just before the colon to increase the concentration of antibiotic in the colon to improve the effectiveness of metronidazole treatment and potentially to allow less whole body exposure to the antibiotic. This study will measure the amount of metronidazole in the blood and stool of patients with C. difficile associated diarrhea (CDAD) to confirm that the new formulations are releasing the antibiotic as designed, immediately before the colon.

All Clinical Trials for FLAGYL

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00195923 ↗	Prospective Randomized Evaluation of Antibiotic Regimen Following Appendectomy for Perforated Appendicitis	Completed	Children's Mercy Hospital Kansas City		2005-04-01	The purpose of this study is to compare traditional triple antibiotic therapy against dual single day dosing antibiotic therapy in the management of perforated appendicitis in children.
NCT00257699 ↗	Study of Antibiotics in the Treatment of Colonic Crohn's Disease	Terminated	Crohn's and Colitis Foundation	Phase 2	2006-05-01	Crohn's disease (CD) is a form of inflammatory bowel disease that can affect any part of the digestive system. Symptoms of this chronic illness include abdominal pain, bloating, nausea, vomiting, and diarrhea. CD also causes bowel wall ulcers, strictures (narrowings of a hollow structure due to scar tissue and swelling), and fistulae (abnormal passages from the intestines to another organ or to the skin). CD is thought to arise from a combination of inherited (genetic) factors and some undefined environmental factor(s). One environmental factor that has been shown to be intimately involved with the development of CD is the presence of bacteria that normally inhabit the intestines. As a result, some physicians have tried to alter the normal bacterial population as a means of controlling the inflammation (swelling) in the intestines of individuals with CD. Among such strategies is the use of a combination of metronidazole and ciprofloxacin. These broad-spectrum antibiotics control CD symptoms by acting on the intestinal bacteria that can contribute to chronic inflammation. More investigation is needed to firmly establish the usefulness of this therapy because previous clinical trials have given mixed results, although they have suggested that antibiotics can be particularly useful in cases of Crohn's colitis (CD that primarily affects the large intestine). Because these earlier studies have lacked a large enough patient population with colonic involvement, a trial focusing on this CD subgroup with a sufficient number of subjects will help to clarify the value of combining metronidazole and ciprofloxacin. The proposed study will test the hypothesis that combination antibiotic therapy is effective in the treatment of CD involving the colon. The study will compare the use of combination therapy consisting of metronidazole and ciprofloxacin with placebo (dummy tablets) and will examine the results of treatment at the end of 8 weeks of treatment.
NCT00257699 ↗	Study of Antibiotics in the Treatment of Colonic Crohn's Disease	Terminated	Mount Sinai Hospital, Canada	Phase 2	2006-05-01	Crohn's disease (CD) is a form of inflammatory bowel disease that can affect any part of the digestive system. Symptoms of this chronic illness include abdominal pain, bloating, nausea, vomiting, and diarrhea. CD also causes bowel wall ulcers, strictures (narrowings of a hollow structure due to scar tissue and swelling), and fistulae (abnormal passages from the intestines to another organ or to the skin). CD is thought to arise from a combination of inherited (genetic) factors and some undefined environmental factor(s). One environmental factor that has been shown to be intimately involved with the development of CD is the presence of bacteria that normally inhabit the intestines. As a result, some physicians have tried to alter the normal bacterial population as a means of controlling the inflammation (swelling) in the intestines of individuals with CD. Among such strategies is the use of a combination of metronidazole and ciprofloxacin. These broad-spectrum antibiotics control CD symptoms by acting on the intestinal bacteria that can contribute to chronic inflammation. More investigation is needed to firmly establish the usefulness of this therapy because previous clinical trials have given mixed results, although they have suggested that antibiotics can be particularly useful in cases of Crohn's colitis (CD that primarily affects the large intestine). Because these earlier studies have lacked a large enough patient population with colonic involvement, a trial focusing on this CD subgroup with a sufficient number of subjects will help to clarify the value of combining metronidazole and ciprofloxacin. The proposed study will test the hypothesis that combination antibiotic therapy is effective in the treatment of CD involving the colon. The study will compare the use of combination therapy consisting of metronidazole and ciprofloxacin with placebo (dummy tablets) and will examine the results of treatment at the end of 8 weeks of treatment.
NCT00353743 ↗	The Use of Antibiotics After Hospital Discharge in Septic Abortion	Terminated	Hospital de Clinicas de Porto Alegre	N/A	2006-05-01	The use of antibiotics in post-partum infection has been abbreviated. After 48 hours of clinical improvement, the patient is discharged from the hospital without antibiotics. No trials has been found in cases of septic abortion. The purpose of the present study is to verify the need of antibiotics after clinical improvement in cases of septic abortion.

Clinical Trial Conditions for FLAGYL

Condition Name

Condition Name for FLAGYL
Intervention	Trials
Helicobacter Pylori Infection	11
Bacterial Vaginosis	6
Crohn's Disease	3
Appendicitis	2

Condition MeSH

Condition MeSH for FLAGYL
Intervention	Trials
Infections	10
Infection	10
Communicable Diseases	8
Helicobacter Infections	8

Clinical Trial Locations for FLAGYL

Trials by Country

Trials by Country for FLAGYL
Location	Trials
United States	39
Taiwan	10
India	8
Canada	6
Brazil	6

Trials by US State

Trials by US State for FLAGYL
Location	Trials
Pennsylvania	4
Michigan	3
North Carolina	3
California	3
Texas	3

Clinical Trial Progress for FLAGYL

Clinical Trial Phase

Clinical Trial Phase for FLAGYL
Clinical Trial Phase	Trials
PHASE2	1
PHASE1	1
Phase 4	26

Clinical Trial Status

Clinical Trial Status for FLAGYL
Clinical Trial Phase	Trials
Completed	37
Unknown status	15
Recruiting	11

Clinical Trial Sponsors for FLAGYL

Sponsor Name

Sponsor Name for FLAGYL
Sponsor	Trials
National Taiwan University Hospital	4
Chang Gung Memorial Hospital	4
National Institute of Allergy and Infectious Diseases (NIAID)	3

Sponsor Type

Sponsor Type for FLAGYL
Sponsor	Trials
Other	101
Industry	20
NIH	5

Clinical Trials Update, Market Analysis, and Projection for Flagyl (metronidazole)

Last updated: April 26, 2026

Flagyl is the brand name for metronidazole, an anti-infective nitroimidazole with a long-established global footprint. As an off-patent, widely genericized product, the market outlook is driven by (1) absolute demand growth in metronidazole-treated indications, (2) price pressure and mix shifts among formulations, and (3) replacement risk from newer regimen standards in select disease areas.

What is Flagyl and what are its core indications?

Flagyl (metronidazole) is approved for multiple bacterial and protozoal infections, including:

• Anaerobic bacterial infections (intra-abdominal, skin/soft tissue, gynecologic infections, dental/odontogenic infections, and related indications depending on country label)
• Protozoal infections, including amoebiasis and trichomoniasis
• Bacterial vaginosis and other gynecologic anaerobic syndromes, depending on region and formulation
• Surgical prophylaxis against anaerobes, depending on local label

FDA labeling information for metronidazole (including Flagyl) lists anaerobic and protozoal uses and includes boxed warnings related to malignancy risk based on animal data, plus a black-box style safety profile in the prescribing information history. (See FDA drug label references in the citations.) [1]

What is the clinical trials pipeline status for Flagyl today?

For metronidazole branded Flagyl, the practical clinical-trials picture is shaped by:

• Dominance of generic submissions and local label updates rather than brand-centric new Phase 3 programs
• Ongoing clinical studies that typically evaluate use in combination regimens, pharmacokinetics in special populations, dosing strategies, and comparative effectiveness against other standard-of-care regimens

A full, current pipeline map requires a live registry scan and is not provided here. This update focuses on what can be supported from authoritative public sources already cited below.

Trials activity that remains “active” in the real world

The ongoing research footprint for metronidazole largely concentrates on:

• Antimicrobial stewardship and resistance monitoring
• Alternative regimens in anaerobic infections and vaginitis indications
• Safety surveillance (neurologic events, cumulative exposure)
• Combination strategies (for example, with other agents in anaerobic infection protocols)

This pattern is consistent with metronidazole’s established role and long time on market, where major new clinical development is generally lower than in patented drugs.

What safety and regulatory constraints shape clinical development and prescribing?

Key safety and regulatory considerations embedded in labeling and real-world use include:

• Neurologic toxicity risk with prolonged or high cumulative dosing (label includes warnings and monitoring language)
• Carcinogenicity signal in animal studies (label includes the malignancy risk communication history)
• Drug-drug interaction risk through metabolism pathways relevant to co-administered therapies

These points drive clinician selection and limits on off-label or extended use, which directly affects volume durability. FDA labeling for metronidazole provides the basis for these warnings. [1]

How big is the metronidazole (Flagyl) market and what drives demand?

Flagyl competes within the metronidazole class, where demand drivers are:

1. High baseline prevalence of susceptible infections
   • Bacterial vaginosis and anaerobic gynecologic infections
   • Anaerobic infections in intra-abdominal, dental/odontogenic, and soft-tissue contexts
2. Protocol stability
   • Many standard-of-care pathways use metronidazole as an anchor drug for anaerobic coverage
3. Generic substitution
   • Brand premium erodes quickly in most markets

Demand structure (directional but actionable)

Flagyl’s commercial reality is that it is a value-oriented, volume-based product. Even when total metronidazole usage grows, revenue growth is constrained by:

• Generic price compression
• Conversion to lowest-cost suppliers
• Formulary exclusion of branded SKUs

Formulation and channel mix

Metronidazole is sold in multiple forms (oral tablets/suspensions, oral/IV formulations depending on market, and other specific presentations by region). In genericized categories, product selection is frequently based on:

• Pricing and procurement contracts
• Hospital formulary and IV availability
• Local guideline alignment and dosing convenience

What does the competitive landscape look like?

The competitive landscape is defined by:

• Large-scale generic manufacturers across major geographies
• Class competition from other anti-anaerobic agents in certain protocols (the degree depends on local guidance and resistance patterns)
• Reimbursement and procurement pressures that reduce brand share

For business planning, the key implication is that Flagyl share is won less by incremental clinical superiority and more by supply reliability, contracting position, and formulation-specific advantages (where any exist).

What is the market outlook and projection for Flagyl (metronidazole)?

Baseline projection framework (volume vs value)

For an off-patent metronidazole product:

• Volume typically tracks infection incidence plus protocol stability
• Value declines with price erosion unless mix shifts into higher-priced SKUs (for example, specific formulations or regulated procurement contracts where branded stock remains)

Practical near-to-midterm expectations

In the absence of a brand-specific Phase 3 breakthrough or label expansion, market performance is more likely to show:

• Stable-to-moderate demand from continuing use in anaerobic and protozoal indications
• Sustained margin pressure from generic substitution
• Potential revenue resilience in markets or channels where branded supply remains contracted or where certain presentations preserve differentiation

Scenario-style directional projection (actionable)

Because no current, registry-validated dataset is included in this response, the projection is framed as scenario logic tied to known market mechanics:

Base case

• Metronidazole volumes remain stable to slightly up due to persistent indication burden
• Revenue growth remains limited; pricing continues to compress

Downside

• Protocol shifts in anaerobic infection pathways reduce metronidazole use in certain settings
• Faster generic price drops and formulary swaps reduce branded revenue faster than volume

Upside

• Procurement contracts favor reliable supply of specific presentations
• Growth in regions with expanding diagnosis and treatment of susceptible infections supports volume

This is the typical profile for long-established, generic-dominant anti-infectives.

What is the clinical-trials and market signal from current evidence?

Metronidazole has an established label and safety profile, which shifts “innovation” from new efficacy claims to:

• local dosing optimization,
• comparative effectiveness within guidelines,
• antimicrobial stewardship and safety monitoring.

That reduces the likelihood of step-change upside for Flagyl revenues unless a jurisdiction creates special access, or a formulation re-enters a protected procurement position. Regulatory and label constraints on safety and risk communication remain central to adoption decisions. [1]

How should investors and R&D leaders use this update for decisions?

For an investment or portfolio allocation focused on Flagyl:

• Treat Flagyl as a cash-generating, contract-driven asset with structural downside from price compression
• Use clinical-trials monitoring for comparator and protocol updates rather than expecting label-defining brand new efficacy
• Focus on formulation and market access mechanics (tenders, hospital contracts, payer coverage) as primary levers

For R&D planning:

• Pursue only programs with clear regulatory differentiation pathways (new formulation, new regimen with defensible claims, or special-population PK/safety packages) since efficacy differentiation in already-standard metronidazole indications is hard to defend

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Key Takeaways

• Flagyl is metronidazole, a long-established, off-patent anti-infective with demand tied to persistent anaerobic and protozoal disease burden.
• The clinical-development landscape is dominated by incremental studies and stewardship rather than brand-defining Phase 3 breakthroughs.
• Market outlook is structurally volume-stable but value-pressure driven by widespread generics and procurement-driven substitution.
• Revenue durability for Flagyl depends more on contract and formulation mix than on clinical pipeline events.
• Label safety constraints (neurologic risk, animal carcinogenicity signal communication) remain prescribing guardrails. [1]

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FAQs

1) Is Flagyl still clinically relevant?

Yes. Metronidazole remains a standard therapy across multiple anaerobic and protozoal indications in many treatment protocols, supported by long-standing regulatory labeling. [1]

2) Does Flagyl face patent expiration risk?

Flagyl itself is already off-patent in practice in most markets due to widespread generic availability. Competitive dynamics are driven by generic substitution rather than patent cliffs.

3) What are the main safety considerations for prescribing?

Metronidazole labeling includes warnings around neurologic toxicity with prolonged exposure and risk communications regarding carcinogenicity signals from animal data. [1]

4) Where does revenue risk come from?

Primary revenue risk is pricing compression and formulary switching to generics, which can reduce branded revenue even if total metronidazole usage stays stable.

5) What would improve the commercial outlook for Flagyl?

Commercial upside would most likely come from secured procurement positions for specific presentations or formulation advantages that preserve contracting power, not from major new efficacy claims.

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References (APA)

[1] U.S. Food and Drug Administration. (n.d.). Flagyl (metronidazole) prescribing information / drug label. FDA. https://www.accessdata.fda.gov/ (accessed via FDA label pages for metronidazole/Flagyl)