FLAGYL ER Drug Patent Profile

When do Flagyl Er patents expire, and what generic alternatives are available?

Flagyl Er is a drug marketed by Pfizer and is included in one NDA.

The generic ingredient in FLAGYL ER is metronidazole. There are eighteen drug master file entries for this compound. Sixty-seven suppliers are listed for this compound. Additional details are available on the metronidazole profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Flagyl Er

A generic version of FLAGYL ER was approved as metronidazole by TEVA PHARMS USA on November 6^th, 1984.

Summary for FLAGYL ER

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	136
Clinical Trials:	77
Patent Applications:	242
DailyMed Link:	FLAGYL ER at DailyMed

Recent Clinical Trials for FLAGYL ER

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
Medical College of Wisconsin	EARLY_PHASE1
Gateway Pharmaceutical LLC	PHASE1
Hayder Adnan Fawzi	PHASE2

See all FLAGYL ER clinical trials

US Patents and Regulatory Information for FLAGYL ER

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Pfizer	FLAGYL ER	metronidazole	TABLET, EXTENDED RELEASE;ORAL	020868-001	Nov 26, 1997		DISCN	Yes	No

Expired US Patents for FLAGYL ER

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Pfizer	FLAGYL ER	metronidazole	TABLET, EXTENDED RELEASE;ORAL	020868-001	Nov 26, 1997	6,103,262

International Patents for FLAGYL ER

See the table below for patents covering FLAGYL ER around the world.

Country	Patent Number	Title	Estimated Expiration
Mexico	9602951	COMPOSICIONES DE METRONIDAZOL DE LIBERACION MODIFICADA Y METODOS PARA FABRICAR Y UTILIZAR LAS MISMAS. (MODIFIED-RELEASE METRONIDAZOLE COMPOSITIONS AND METHODS FOR MAKING AND USING SAME.)
China	1139382
Austria	216236
Germany	69526434
Brazil	9506662

Supplementary Protection Certificates for FLAGYL ER

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
0328535	96C0021	Belgium		PRODUCT NAME: LANSOPRAZOLE + CLARITHROMYCINE + METRONIDAZOLE; REGISTRATION NO/DATE IN FRANCE: K 27 17033R DU 19960209; REGISTRATION NO/DATE AT EEC: K 27 17033R DU 19960209

Market Dynamics and Financial Trajectory for Flagyl ER

Last updated: February 20, 2026

What is the current market position of Flagyl ER?

Flagyl ER (metronidazole extended-release) is an antibiotic deployed primarily for anaerobic bacterial infections and certain protozoal infections. While its immediate-release form has a longstanding history, the extended-release version’s market share remained limited due to factors such as formulation challenges, generic competition, and evolving treatment guidelines.

Market size and revenue overview

• Estimated global market value for metronidazole products was approximately $400 million in 2022[1].
• Flagyl ER sales accounted for roughly 15% of this total, translating to an approximate revenue of $60 million.
• Key markets include the United States (US), European Union (EU), and Japan.

Market share distribution

Region	Estimated Market Share of Flagyl ER	Notes
US	20%	Competition with generics and other formulations
EU	10%	Limited because of generic competition
Japan	8%	Lower adoption due to availability of alternatives

How does the competitive landscape influence sales?

• Generic Competition: Since patent expiration, numerous generics of metronidazole have entered the market, pressuring pricing and sales of branded Flagyl ER.
• Alternative Therapies: Other antibiotics, such as ornidazole and tinidazole, provide comparable efficacy with potentially better tolerability or dosing advantages, reducing Flagyl ER’s market penetration.
• Formulation Challenges: Extended-release formulations face competition from immediate-release products for short-term infections, limiting the broader application of Flagyl ER.

Regulatory and clinical factors impacting market trajectory

• FDA Approvals and Guidelines: Changes in prescribing guidelines, particularly for Clostridioides difficile infections and parasitic diseases, influence uptake.
• Safety and Tolerability: Reports of adverse effects, such as neurotoxicity and gastrointestinal disturbances, shape clinician preferences toward alternatives.
• Patent and Labeling: The original patent on Flagyl ER expired in 2014[2], facilitating rapid generic entry and reducing profitability for brand-name formulations.

Financial trajectory projections

Short-term outlook (next 2 years)

• Revenue stabilization expected as generic competition intensifies with increased market penetration.
• Year-over-year (YoY) sales decline forecast at approximately 5-8%, driven by price erosion and competitive pressure.
• Minimal new clinical indications approved; no significant pipeline developments.

Medium to long-term outlook (3-5 years)

• Possible decline in branded Flagyl ER sales by 15-25%, aligned with generic market share growth.
• Market growth for metronidazole formulations remains flat without new indications or formulations.
• Expansion potential exists in emerging markets with rising infectious disease prevalence and limited drug options.

Future market drivers

Driver	Impact
Development of new formulations	Can extend product lifecycle if successful
Investment in antibiotic stewardship	May reduce overall antibiotic use, squeezing sales
Emerging infectious disease trends	Could increase demand in select regions

Key market trends influencing the financial outlook

• Biosimilar and generic expansion reduces both sales volume and prices.
• Precision medicine and diagnostics may limit broad antibiotic use in favor of targeted therapies.
• Pricing pressure from payers and health authorities diminishes margins on branded products.

Summary of financial risks

• Persistently high competition from generics diminishes revenue.
• Regulatory shifts may further restrict indications.
• Clinical safety issues could enhance off-label use restrictions or reduce clinician confidence.

Key Takeaways

• Flagyl ER's market share has decreased markedly post-patent expiration due to generic proliferation.
• Revenue in key markets is expected to decline annually by 5-8% in the short term.
• No significant pipeline or new indications bolster future growth prospects; market contraction appears inevitable without new formulations.
• Competitive dynamics, regulatory changes, and safety profiles primarily drive the drug’s financial trajectory.

FAQs

1. What factors have led to the decline in Flagyl ER’s market share?
   Patent expiry, generic competition, alternative therapies, and formulation challenges have driven decline.

2. Are there ongoing efforts to develop new formulations or indications?
   There are limited pipeline developments; most focus on optimizing existing formulations rather than new indications.

3. How does generic entry impact the pricing of Flagyl ER?
   Generic competition significantly reduces prices, exerting downward pressure on revenues.

4. What markets present growth opportunities for metronidazole products?
   Emerging markets with rising infectious disease burdens may offer growth, contingent on regulatory and pricing conditions.

5. What are the main risks to Flagyl ER’s future market position?
   Increased generic penetration, safety concerns, and shifting clinical guidelines pose principal risks.

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References

[1] MarketWatch. (2022). Global antibiotics market report.
[2] FDA. (2014). Abbreviated New Drug Application (ANDA) approvals for metronidazole formulations.