Paroxetine mesylate - Generic Drug Details

What are the generic drug sources for paroxetine mesylate and what is the scope of freedom to operate?

Paroxetine mesylate is the generic ingredient in three branded drugs marketed by Legacy Pharma, Actavis Labs Fl Inc, Prinston Inc, and Sebela Ireland Ltd, and is included in four NDAs. There are three patents protecting this compound and one Paragraph IV challenge. Additional information is available in the individual branded drug profile pages.

Paroxetine mesylate has forty-four patent family members in twenty-six countries.

There are two drug master file entries for paroxetine mesylate. Three suppliers are listed for this compound.

Summary for paroxetine mesylate

International Patents:	44
US Patents:	3
Tradenames:	3
Applicants:	4
NDAs:	4
Drug Master File Entries:	2
Finished Product Suppliers / Packagers:	3
Raw Ingredient (Bulk) Api Vendors:	33
Clinical Trials:	5
Patent Applications:	348
Drug Prices:	Drug price trends for paroxetine mesylate
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for paroxetine mesylate
What excipients (inactive ingredients) are in paroxetine mesylate?	paroxetine mesylate excipients list
DailyMed Link:	paroxetine mesylate at DailyMed

See drug prices for paroxetine mesylate

Recent Clinical Trials for paroxetine mesylate

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

Sponsor	Phase
Alphacait, LLC	Phase 2
Haining Health-Coming Biotech Co., Ltd.	Phase 2
Noven Therapeutics	Phase 1

See all paroxetine mesylate clinical trials

Pharmacology for paroxetine mesylate

Drug Class	Serotonin Reuptake Inhibitor
Mechanism of Action	Serotonin Uptake Inhibitors

Anatomical Therapeutic Chemical (ATC) Classes for paroxetine mesylate

N06AB	Selective serotonin reuptake inhibitors
N06A	ANTIDEPRESSANTS
N06	PSYCHOANALEPTICS
N	Nervous system

Paragraph IV (Patent) Challenges for PAROXETINE MESYLATE

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
BRISDELLE	Capsules	paroxetine mesylate	7.5 mg	204516	1	2014-04-07

US Patents and Regulatory Information for paroxetine mesylate

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Prinston Inc	PAROXETINE MESYLATE	paroxetine mesylate	CAPSULE;ORAL	207188-001	Aug 18, 2017	AB	RX	No	No
Legacy Pharma	BRISDELLE	paroxetine mesylate	CAPSULE;ORAL	204516-001	Jun 28, 2013	AB	RX	Yes	Yes	8,946,251		Y	Y
Sebela Ireland Ltd	PEXEVA	paroxetine mesylate	TABLET;ORAL	021299-003	Jul 3, 2003		DISCN	Yes	No
Legacy Pharma	BRISDELLE	paroxetine mesylate	CAPSULE;ORAL	204516-001	Jun 28, 2013	AB	RX	Yes	Yes	8,658,663		Y	Y
Sebela Ireland Ltd	PEXEVA	paroxetine mesylate	TABLET;ORAL	021299-004	Jul 3, 2003		DISCN	Yes	No
Sebela Ireland Ltd	PEXEVA	paroxetine mesylate	TABLET;ORAL	021299-001	Jul 3, 2003		DISCN	Yes	No
Actavis Labs Fl Inc	PAROXETINE MESYLATE	paroxetine mesylate	CAPSULE;ORAL	207139-001	Jun 20, 2017	AB	RX	No	No

Expired US Patents for paroxetine mesylate

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Sebela Ireland Ltd	PEXEVA	paroxetine mesylate	TABLET;ORAL	021299-001	Jul 3, 2003	5,874,447
Legacy Pharma	BRISDELLE	paroxetine mesylate	CAPSULE;ORAL	204516-001	Jun 28, 2013	5,874,447
Sebela Ireland Ltd	PEXEVA	paroxetine mesylate	TABLET;ORAL	021299-002	Jul 3, 2003	5,874,447
Sebela Ireland Ltd	PEXEVA	paroxetine mesylate	TABLET;ORAL	021299-002	Jul 3, 2003	7,598,271
Sebela Ireland Ltd	PEXEVA	paroxetine mesylate	TABLET;ORAL	021299-003	Jul 3, 2003	5,874,447
Sebela Ireland Ltd	PEXEVA	paroxetine mesylate	TABLET;ORAL	021299-001	Jul 3, 2003	7,598,271
Sebela Ireland Ltd	PEXEVA	paroxetine mesylate	TABLET;ORAL	021299-003	Jul 3, 2003	7,598,271

International Patents for paroxetine mesylate

Country	Patent Number	Title	Estimated Expiration
Russian Federation	2009107739	СПОСОБ ЛЕЧЕНИЯ РАССТРОЙСТВА ТЕРМОРЕГУЛЯЦИИ
Israel	196844
Japan	2009545593
Portugal	2719385
World Intellectual Property Organization (WIPO)	2008019010
Japan	5895009
Japan	2014077023

Market Dynamics and Financial Trajectory for Paroxetine Mesylate

Last updated: February 19, 2026

Paroxetine mesylate, marketed as Paxil among other names, is an SSRI (selective serotonin reuptake inhibitor) indicated primarily for depression, anxiety disorders, and obsessive-compulsive disorder. Its market landscape has shifted significantly over the past decade due to patents, generic entry, and evolving treatment guidelines.

Market Size and Revenue Trends

Global sales of paroxetine peaked prior to patent expiry, reaching approximately $1.2 billion in 2011 (GlobeNewswire, 2021). Post-patent expiration in 2012, the market experienced an influx of generics, sharply reducing brand-name revenues.

Year	Estimated Global Sales (USD billion)	Key Events
2010	1.2	Patent protection ongoing
2012	0.4	Patent expiration, generic entry begins
2015	0.15	Market largely dominated by generics
2020	0.1	Declining use due to newer antidepressants

The reduction in revenue is primarily attributable to generic competition. Brand-name sales now account for less than 10% of 2012 levels in major markets such as the U.S. and Europe.

Patent and Regulatory Milestones

Paroxetine was patented in the United States in 1985, with patents held until 2012 (U.S. Patent and Trademark Office, 2012). The expiration led to widespread generic manufacturing.

The drug has been approved by regulatory agencies such as FDA and EMA for multiple indications, including major depressive disorder, generalized anxiety disorder, panic disorder, and social anxiety disorder.

Competitive Landscape

The therapeutic class is saturated with several SSRIs, such as fluoxetine, sertraline, and escitalopram, which have replaced paroxetine in many treatment protocols. Generics are manufactured by numerous companies, including Teva, Mylan, and Sandoz.

Company	Market Share (2019)	Product Status
Teva	35%	Market leader for generic paroxetine
Mylan	25%	Significant presence in retail pharmacies
Sandoz	20%	Active in Europe and emerging markets
Others	20%	Multiple regional companies

The entry of generics reduced profit margins for originators and shifted focus toward biosimilars and newer treatment options.

Pricing and Reimbursement Policies

Pricing in the U.S. varies significantly between brand-name and generics. The average retail price for a 20 mg tablet in 2022 was approximately USD 4 for generics, versus USD 20 for Paxil (GoodRx, 2022). Reimbursement policies favor generics to control healthcare costs, further squeezing profits on branded formulations.

Future Outlook

The outlook for paroxetine mesylate focuses on the following factors:

• Market decline: Continued erosion in revenue as generics dominate.
• Pipeline stagnation: Limited new indications or reformulations.
• Regulatory environment: Increased scrutiny on antidepressants for off-label uses.
• Emerging markets: Growth in regions with limited access to newer antidepressants could sustain sales levels, albeit at low margins.

Investment and R&D Considerations

investment in paroxetine is unlikely to yield substantial returns due to market saturation and patent loss. Companies are shifting R&D resources toward novel mechanisms, such as ketamine derivatives for depression, or combination therapies.

Existing generic manufacturers are unlikely to invest heavily in process improvements or marketing for established formulations, focusing resources on newer drugs or biosimilars.

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Key Takeaways

• Paroxetine mesylate's global peak sales of $1.2 billion in 2011 have declined to approximately $100 million in recent years.
• Patent expiration in 2012 resulted in extensive generic competition, reducing profitability for original developers.
• The drug faces stiff competition from other SSRIs, with limited new indications or formulations in development.
• Pricing pressures and reimbursement policies favor generics, further commoditizing the market.
• Limited pipeline prospects suggest minimal future growth, with most companies shifting R&D toward novel antidepressants.

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FAQs

1. Why did paroxetine's market decline so sharply after 2012?
   Patent expiration allowed generics to enter, drastically reducing brand-name market share and revenues.

2. Are there any new formulations or indications for paroxetine?
   No significant new formulations or indications have been approved in recent years.

3. How does paroxetine compare to other SSRIs in terms of usage?
   It remains less favored compared to newer SSRIs like escitalopram, due to side-effect profiles and availability of alternatives.

4. What regions have the highest future potential for paroxetine sales?
   Emerging markets with limited access to newer antidepressants may sustain some sales, but overall growth is limited.

5. Is there ongoing R&D for paroxetine or its class?
   No significant R&D efforts are underway for paroxetine; focus has shifted to newer drugs with better safety and efficacy profiles.

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References

[1] GlobeNewswire. (2021). Paroxetine Market Analysis.
[2] U.S. Patent and Trademark Office. (2012). Patent status for paroxetine.
[3] GoodRx. (2022). Price comparison for paroxetine.