FOSPHENYTOIN SODIUM - Generic Drug Details

What are the generic sources for fosphenytoin sodium and what is the scope of patent protection?

Fosphenytoin sodium is the generic ingredient in three branded drugs marketed by Parke Davis, Am Regent, Amneal, Apotex Inc, Dr Reddys, Fresenius Kabi Usa, Gland, Hikma, Hikma Farmaceutica, Hospira, Pharmobedient, Sun Pharm, Wockhardt Bio Ag, and Lupin, and is included in sixteen NDAs. There are five patents protecting this compound. Additional information is available in the individual branded drug profile pages.

Fosphenytoin sodium has fifty-four patent family members in fourteen countries.

There are eight drug master file entries for fosphenytoin sodium. Eight suppliers are listed for this compound.

Summary for FOSPHENYTOIN SODIUM

International Patents:	54
US Patents:	5
Tradenames:	3
Applicants:	14
NDAs:	16
Drug Master File Entries:	8
Finished Product Suppliers / Packagers:	8
Raw Ingredient (Bulk) Api Vendors:	1
Clinical Trials:	3
Patent Applications:	1,722
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for FOSPHENYTOIN SODIUM
What excipients (inactive ingredients) are in FOSPHENYTOIN SODIUM?	FOSPHENYTOIN SODIUM excipients list
DailyMed Link:	FOSPHENYTOIN SODIUM at DailyMed

Recent Clinical Trials for FOSPHENYTOIN SODIUM

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

Sponsor	Phase
Nobelpharma	Phase 3
Shaheed Zulfiqar Ali Bhutto Medical University	N/A
Banaras Hindu University	Phase 2

See all FOSPHENYTOIN SODIUM clinical trials

Pharmacology for FOSPHENYTOIN SODIUM

Drug Class	Anti-epileptic Agent
Mechanism of Action	Cytochrome P450 1A2 Inducers Cytochrome P450 2B6 Inducers Cytochrome P450 2C19 Inducers Cytochrome P450 2C8 Inducers Cytochrome P450 2C9 Inducers Cytochrome P450 2D6 Inducers Cytochrome P450 3A Inducers
Physiological Effect	Decreased Central Nervous System Disorganized Electrical Activity

Anatomical Therapeutic Chemical (ATC) Classes for FOSPHENYTOIN SODIUM

N03AB	Hydantoin derivatives
N03A	ANTIEPILEPTICS
N03	ANTIEPILEPTICS
N	Nervous system

N03AB	Hydantoin derivatives
N03A	ANTIEPILEPTICS
N03	ANTIEPILEPTICS
N	Nervous system

US Patents and Regulatory Information for FOSPHENYTOIN SODIUM

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Dr Reddys	FOSPHENYTOIN SODIUM	fosphenytoin sodium	INJECTABLE;INJECTION	076886-001	Aug 6, 2007		DISCN	No	No
Lupin	SESQUIENT	fosphenytoin sodium	SOLUTION;INTRAVENOUS	210864-002	Nov 5, 2020		DISCN	Yes	No	8,410,077		Y
Am Regent	FOSPHENYTOIN SODIUM	fosphenytoin sodium	INJECTABLE;INJECTION	078277-001	Aug 6, 2007		DISCN	No	No
Hikma	FOSPHENYTOIN SODIUM	fosphenytoin sodium	INJECTABLE;INJECTION	077481-001	Aug 6, 2007	AP	RX	No	No

Expired US Patents for FOSPHENYTOIN SODIUM

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Parke Davis	CEREBYX	fosphenytoin sodium	INJECTABLE;INJECTION	020450-001	Aug 5, 1996	4,260,769
Parke Davis	CEREBYX	fosphenytoin sodium	INJECTABLE;INJECTION	020450-001	Aug 5, 1996	4,925,860

International Patents for FOSPHENYTOIN SODIUM

Country	Patent Number	Title	Estimated Expiration
Russian Federation	2615385	КОМПОЗИЦИИ АЛКИЛИРОВАННОГО ЦИКЛОДЕКСТРИНА И СПОСОБЫ ИХ ПОЛУЧЕНИЯ И ПРИМЕНЕНИЯ (ALKYLATED CYCLODEXTRIN COMPOSITIONS AND PROCESSES FOR PREPARING AND USING THE SAME RELATED APPLICATIONS)
Russian Federation	2016140391	КОМПОЗИЦИИ АЛКИЛИРОВАННОГО ЦИКЛОДЕКСТРИНА И СПОСОБЫ ИХ ПОЛУЧЕНИЯ И ПРИМЕНЕНИЯ
Canada	2702603
Mexico	352459	COMPOSICIONES DE ETER-SULFOALQUILICO-CICLODEXTRINA. (SULFOALKYL ETHER CYCLODEXTRIN COMPOSITIONS.)

Supplementary Protection Certificates for FOSPHENYTOIN SODIUM

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
0473687	SPC/GB98/030	United Kingdom		PRODUCT NAME: FOSPHENYTOIN SODIUM (3-HYDROXYMETHYL)-5,5-DIPHENYLHYDANTOIN DISODIUM PHOSPHATE ESTER); REGISTERED: UK 0019/0157 19980204
0473687	99C0008	Belgium		PRODUCT NAME: FOSPHENYTOINUM DINATRICUM; REGISTRATION NO/DATE: 19 IS 102 F12 19980901; FIRST REGISTRATION: GB PL00019/1057 19980204
0145340	99C0005	Belgium		PRODUCT NAME: FOSPHENYTOIN DISODIUM; NAT. REGISTRATION NO/DATE: NL 23 613 19980806; FIRST REGISTRATION: GB - PL 000 19/0157 19980204
0473687	C980045	Netherlands		PRODUCT NAME: FOSPHENYTOINUM-DI-NATRICUM; NATL REGISTRATION NO/DATE: RVG 22758 19980702; FIRST REGISTRATION: GB PL 00019/0157 19980204

Market Dynamics and Financial Trajectory for Fosphenytoin Sodium

Last updated: July 27, 2025

Introduction

Fosphenytoin sodium, a prodrug of phenytoin, primarily functions as an anticonvulsant used to manage seizure activity in diverse clinical settings. Since its FDA approval in 2004, fosphenytoin has gained prominence as an alternative to traditional phenytoin, offering improved safety profiles and ease of administration. This analysis explores the current market dynamics, competitive landscape, regulatory environment, and financial trajectory shaping fosphenytoin sodium’s industry outlook.

Market Overview

The global anticonvulsant drugs market is projected to exceed USD 10 billion by 2025, driven by increasing incidences of epilepsy, traumatic brain injuries, and stroke-related seizures [1]. Fosphenytoin comprises a significant portion within this landscape, targeting secondary care settings such as hospitals, emergency departments, and critical care units. Its higher tolerability compared to phenytoin fuels demand, especially for intravenous (IV) formulations preferred in acute scenarios.

Key Drivers

• Clinical Advantages: Fosphenytoin offers advantages such as reduced risk of infusion site reactions and less need for cardiac monitoring, which enhances its appeal among neurologists and emergency physicians [2].
• Regulatory Approvals and Off-Label Use: While FDA approval underpins its credibility, off-label indications and evolving guidelines on seizure management continue to influence prescribing patterns.
• Aging Population & Rising Seizure Incidence: The global demographic shift towards an older population amplifies the incidence of epilepsy and seizure-related complications, fostering sustained demand.
• Hospital and Critical Care Spending: Growth in hospital admissions and intensive care units (ICUs) promotes procurement of fosphenytoin for acute seizure control.

Market Restraints

• Generic Competition: Fosphenytoin’s patent expired, leading to increased availability of cheaper generic versions, thus exerting downward pressure on prices [3].
• Alternative Therapies: The emergence of newer anticonvulsants such as levetiracetam and lacosamide, characterized by favorable safety profiles, threaten fosphenytoin’s market share.
• Regulatory and Prescribing Trends: Some regulatory bodies advocate for the use of newer agents, supported by long-term safety data and simplified dosing.

Competitive Landscape

Major players include Pfizer (original manufacturer), Teva Pharmaceuticals, Mylan (now part of Viatris), and Apotex, among others. Pfizer’s original product, branded as Cerebyx, faces generic competition, which accounts for a significant portion of the market share. The commoditization of fosphenytoin has led to price erosion, impacting revenue growth prospects.

Innovative device integration, such as ready-to-use IV formulations, and strategic collaborations are observed strategies among key firms to maintain competitiveness. Additionally, pipeline development for related prodrugs and combination therapies signifies industry efforts to broaden therapeutic applications.

Regulatory Environment and Patent Landscape

The expiration of Pfizer’s patent rights around 2015 spurred a surge in generic manufacturing. The FDA’s ongoing surveillance of anticonvulsant safety and approvals for new indications influence market trajectories. Patent cliff effects combined with regulatory scrutiny may introduce volatility but also open avenues for biosimilar entry in the future.

Financial Trajectory and Revenue Outlook

Historical Performance

Pfizer’s sales of Cerebyx peaked pre-patent expiry, estimated at around USD 300 million annually [4]. Post-generic entry, revenues declined sharply, a trend mirrored across competitors producing generic fosphenytoin.

Future Projections

Analysts predict modest recovery or stabilization may occur owing to rising seizure prevalence and hospital procurement patterns. However, the overall revenue growth is likely to remain stagnant or decline marginally due to intense price competition and substitutive therapies.

The global adoption of alternative antiepileptics, particularly in outpatient and long-term management, diminishes fosphenytoin’s market penetration outside acute care. Nevertheless, demand for IV formulations in emergency medicine ensures continued revenue streams, primarily within hospital settings.

Market Opportunities

• Expansion in Emerging Markets: Growing healthcare infrastructures and epilepsy awareness in Asia-Pacific and Latin America pose untapped growth opportunities.
• New Formulation Developments: Innovative delivery systems, including pre-filled syringes and controlled-release formulations, could command premium pricing.
• Combination Therapies: Research into fosphenytoin’s adjunct use with novel agents may unlock new therapeutic niches.

Risks and Uncertainties

• The emergence of oral, safer, and more convenient anticonvulsants.
• Potential regulatory shifts favoring newer compounds.
• Pricing pressures in commoditized markets.
• Fluctuations in hospital procurement policies post-pandemic.

Conclusion

Fosphenytoin sodium’s market remains characterized by significant patent expiry-driven commoditization, compounded by competition from newer, better-tolerated anticonvulsants. While acute care demands sustain a baseline revenue, long-term growth prospects hinge on strategic innovation, geographic expansion, and clinical positioning. Pharma companies navigating these dynamics must balance cost competitiveness, regulatory pressures, and clinical trends to optimize financial outcomes.

Key Takeaways

• Fosphenytoin’s core market focus is acute seizure management within hospital settings, making it sensitive to hospital procurement trends.
• Patent expiry has led to widespread generic competition, suppressing pricing power.
• The rise of newer anticonvulsants and shifting clinical guidelines challenge fosphenytoin’s long-term growth.
• Opportunities lie in expanding into emerging markets and developing innovative formulations.
• Financial planning should consider market saturation, competitive pressures, and regulatory developments influencing revenue trajectories.

FAQs

1. How does fosphenytoin differ from phenytoin in clinical use?
Fosphenytoin offers a more tolerable administration route with fewer infusion site reactions, a lower risk of cardiac arrhythmias, and simplified dosing, especially suitable for IV and IM use in acute settings. It’s designed as a prodrug that converts to phenytoin in vivo.

2. What factors are influencing the decline in fosphenytoin revenues?
Patent expiration leading to generics, competition from newer anticonvulsants like levetiracetam, safety and tolerability advantages of alternatives, and evolving clinical guidelines favoring these agents contribute to revenue declines.

3. Are there any promising pipeline developments for fosphenytoin?
Current pipeline efforts focus more on alternative formulations and combination therapies for seizure management rather than novel fosphenytoin-specific drugs, limiting potential near-term pipeline breakthroughs.

4. How significant is the market potential in emerging markets for fosphenytoin?
Emerging markets represent a growing segment due to increasing epilepsy awareness and healthcare infrastructure development, offering significant growth opportunities amid a relatively low drug penetration.

5. What strategies can pharmaceutical firms adopt to sustain fosphenytoin’s market presence?
Strategies include innovating delivery systems, focusing on hospital procurement channels, pursuing geographic expansion, and leveraging clinical data to validate its role in acute seizure management.

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References:

[1] MarketsandMarkets. “Anticonvulsant Drugs Market by Drug Type, Application, and Region – Global Forecast to 2025.”
[2] US FDA. “Cerebyx (Fosphenytoin Sodium) Prescribing Information.”
[3] IQVIA. “Generic Drug Market Trends and Patent Expirations.”
[4] Pfizer Annual Reports. “Historical Sales Data for Cerebyx.”