Ethotoin - Generic Drug Details

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

Ethotoin is the generic ingredient in one branded drug marketed by Recordati Rare and is included in one NDA. Additional information is available in the individual branded drug profile pages.

Summary for ethotoin

US Patents:	0
Tradenames:	1
Applicants:	1
NDAs:	1
Drug Master File Entries:	1
Raw Ingredient (Bulk) Api Vendors:	44
Clinical Trials:	1
What excipients (inactive ingredients) are in ethotoin?	ethotoin excipients list
DailyMed Link:	ethotoin at DailyMed

Recent Clinical Trials for ethotoin

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

Sponsor	Phase
Federal University of São Paulo	Phase 4
Fundação de Amparo à Pesquisa do Estado de São Paulo	Phase 4

See all ethotoin clinical trials

Anatomical Therapeutic Chemical (ATC) Classes for ethotoin

N03AB	Hydantoin derivatives
N03A	ANTIEPILEPTICS
N03	ANTIEPILEPTICS
N	Nervous system

US Patents and Regulatory Information for ethotoin

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Recordati Rare	PEGANONE	ethotoin	TABLET;ORAL	010841-003	Approved Prior to Jan 1, 1982		DISCN	No	No
Recordati Rare	PEGANONE	ethotoin	TABLET;ORAL	010841-001	Approved Prior to Jan 1, 1982		DISCN	Yes	No

Ethotoin Market Dynamics and Financial Trajectory

Last updated: September 7, 2026

Ethotoin is a mature hydantoin anticonvulsant with negligible current commercial importance in the United States. The drug was marketed primarily as Peganone for generalized tonic-clonic and complex partial seizures. Its market declined as newer antiseizure medicines gained adoption, while phenytoin, carbamazepine, valproate and later-generation therapies provided stronger prescribing alternatives. No current public filing reports standalone ethotoin revenue, and the product does not have a meaningful role in the modern branded pharmaceutical market.

What is ethotoin and how is it used?

Ethotoin is an oral antiepileptic in the hydantoin class. It is structurally related to phenytoin and acts primarily through neuronal sodium-channel inhibition, reducing high-frequency repetitive neuronal firing.

The historical U.S. product was Peganone, supplied as 250-milligram and 500-milligram tablets. The FDA labeling identified the drug for management of tonic-clonic seizures and psychomotor, now generally called focal impaired-awareness, seizures. It was not considered effective for absence seizures and was not positioned as a broad-spectrum treatment for all epilepsy types (U.S. Food and Drug Administration [FDA], n.d.-a).

Attribute	Ethotoin
Active ingredient	Ethotoin
Historical brand	Peganone
Therapeutic class	Hydantoin anticonvulsant
Dosage form	Immediate-release oral tablet
Historical strengths	250 mg and 500 mg
Main indications	Tonic-clonic and psychomotor seizures
Primary market	Legacy epilepsy treatment
Current commercial position	Limited or unavailable in the U.S. market
Biosimilar exposure	None
Standalone public revenue	Not reported

When did ethotoin lose commercial momentum?

Ethotoin lost commercial momentum over several decades rather than through a single patent event. The main factors were clinical substitution, limited differentiation and declining physician familiarity.

Phenytoin offered a better-established clinical profile within the same broad therapeutic class. Carbamazepine and valproate expanded treatment options for focal and generalized epilepsies. Newer drugs such as lamotrigine, levetiracetam, topiramate, oxcarbazepine and lacosamide later gained share because of simpler dosing, broader indications, fewer interactions or improved tolerability in selected patients.

Ethotoin also faced the standard disadvantages of older antiseizure medicines:

• Narrow therapeutic positioning.
• Limited use outside specific seizure types.
• Drug-interaction concerns associated with hepatic metabolism.
• Need for continued clinical monitoring.
• Low commercial incentive to maintain distribution for a small patient population.
• Lack of a differentiated delivery system or extended-release formulation.

The market therefore contracted through prescription substitution and declining availability. This differs from a conventional branded product facing a sudden generic cliff. For ethotoin, the more important commercial event was the erosion of demand and manufacturing interest.

What is the FDA regulatory status of ethotoin?

Ethotoin is not a meaningful current U.S. growth product. Public FDA resources identify historical ethotoin labeling and product records, but current availability should be distinguished from historical approval.

The FDA’s Orange Book separates active approved products from discontinued products. A drug can remain associated with an approved application or historical labeling without being broadly marketed. The Orange Book also does not guarantee that a listed product is commercially available from a manufacturer or wholesaler (FDA, n.d.-b).

Regulatory question	Commercial implication
Was ethotoin historically FDA approved?	Yes, under the Peganone product history
Is historical approval equivalent to current supply?	No
Is ethotoin a current major FDA-market product?	No
Does it have modern biologic or specialty-drug exclusivity?	No
Is it subject to biosimilar substitution?	No
Does its market depend on current manufacturer support?	Yes

The historical FDA label remains relevant for dosing, contraindications and seizure-type limitations. It does not establish active commercial supply. Availability has varied by period and jurisdiction, and the U.S. market has not supported a visible, scaled ethotoin franchise.

What patents protect ethotoin?

Ethotoin is an old small-molecule drug, and its primary composition-of-matter protection is long expired. Any original patent protection would have ended many decades ago, well before the modern patent-term framework.

The commercial patent estate is therefore weak from an exclusivity perspective:

Patent category	Current relevance
Original ethotoin compound patent	Expired
Original Peganone product patent	Expired or commercially irrelevant
Basic tablet formulation	Not a meaningful barrier
Method-of-use patents	No material modern exclusivity identified
Manufacturing patents	Possible process know-how, but unlikely to support market exclusivity
Pediatric exclusivity	Not material
Orphan-drug exclusivity	Not applicable
Patent-term extension	Not commercially relevant

No patent-based barrier prevents a qualified manufacturer from pursuing an ethotoin product if regulatory, technical and economic requirements can be met. The main constraints are market size, manufacturing economics, clinical demand and supply-chain commitment.

Does ethotoin have Orange Book listings or Paragraph IV risk?

Any historical Orange Book presence does not create a current high-value Paragraph IV opportunity. Paragraph IV litigation is economically attractive when a branded product has substantial sales, active patents and a clear generic market. Ethotoin lacks those characteristics.

A potential generic manufacturer would face a different decision:

1. Confirm that a reference product and regulatory pathway remain available.
2. Establish bioequivalence for the relevant tablet strengths.
3. Secure an active pharmaceutical ingredient source.
4. Estimate the small and declining addressable market.
5. Determine whether wholesalers and pharmacies would stock the product.
6. Evaluate regulatory maintenance costs against expected volume.

The litigation profile is therefore minimal. There is no widely recognized current patent dispute involving ethotoin comparable to disputes surrounding high-revenue oncology, immunology or metabolic drugs. Any Paragraph IV filing would be driven by niche supply economics rather than a large branded-revenue opportunity.

How large is the ethotoin market?

A reliable current market-size figure is not available from public company disclosures or standard commercial reporting. Ethotoin is generally absent from major pharmaceutical growth-market analyses because it is not a material contributor to branded sales.

The commercial market can be characterized as follows:

Market metric	Assessment
Current branded sales	Not publicly reported as material
Public company revenue disclosure	No standalone ethotoin reporting
Prescription growth	Structurally declining
Pricing power	Low
Generic competition	Potentially available in principle, but limited in practice
Prescriber base	Narrow and concentrated
Distribution	Dependent on specialty or legacy-product supply
Market expansion potential	Very low

The lack of public revenue reporting is itself informative. Products with meaningful commercial exposure generally appear in company segment reporting, investor presentations, earnings calls or market-share datasets. Ethotoin does not have that profile.

Its remaining demand would likely come from patients who are stable on the medicine, clinicians managing treatment continuity, or settings where alternative antiseizure medicines are unsuitable. That demand can persist even after a product becomes commercially marginal, but persistence does not imply market growth.

What is the financial trajectory for ethotoin?

Ethotoin’s financial trajectory is best described as long-term revenue decay followed by commercial rationalization.

Historical phase

Peganone entered a market in which older anticonvulsants had established clinical roles. Early revenue would have benefited from limited therapeutic competition and the absence of many modern antiseizure alternatives.

Mature phase

As epilepsy treatment expanded, ethotoin became a secondary or niche option. Prescribers increasingly used products with broader seizure coverage, more familiar dosing protocols and better commercial support. The drug’s mature-market revenue likely declined in unit volume and became increasingly dependent on legacy patients.

Late-commercial phase

At low volume, fixed costs become significant. A manufacturer must maintain:

• Validated manufacturing processes.
• Quality-control testing.
• Stability data.
• Regulatory filings.
• Pharmacovigilance.
• Packaging and labeling.
• Distribution arrangements.
• Pharmacist and prescriber support.

For an old tablet with limited demand, these costs can exceed the value of incremental sales. The rational commercial outcome is often discontinuation, supply reduction or transfer to a smaller manufacturer rather than investment in promotion.

Current phase

Ethotoin has no identifiable high-growth commercial pathway. Revenue is likely negligible relative to the portfolios of major pharmaceutical companies. Any surviving sales would be maintenance revenue from a small installed patient base, not revenue from market expansion.

How does ethotoin compare with competing antiseizure drugs?

Ethotoin is disadvantaged against both older competitors and modern therapies.

Drug	Market position	Competitive advantage over ethotoin
Phenytoin	Established legacy anticonvulsant	Broader historical use and stronger clinical familiarity
Carbamazepine	Major focal-seizure treatment	Stronger guideline position for focal epilepsy
Valproate	Broad-spectrum antiseizure drug	Broader seizure coverage
Lamotrigine	Established modern therapy	More favorable use in several chronic-treatment settings
Levetiracetam	High-volume modern therapy	Simpler use and extensive current availability
Lacosamide	Branded and generic focal-seizure therapy	Modern positioning and commercial support
Ethotoin	Niche legacy product	Limited differentiation and availability

The closest historical comparison is phenytoin, but ethotoin lacks phenytoin’s entrenched clinical use and market recognition. Compared with levetiracetam or lamotrigine, ethotoin has limited commercial relevance.

Are there formulation or manufacturing barriers?

There is no apparent formulation technology protecting ethotoin from competition. The historical product was an immediate-release tablet, not a complex injectable, controlled-release system, inhaled product or biologic.

Manufacturing barriers are operational rather than intellectual-property based. A manufacturer must produce consistent tablets, meet current good manufacturing practice requirements and demonstrate regulatory conformity. The active ingredient may also be difficult to source at economical scale if global demand is very low.

This creates a paradox for generic entry. The absence of patents makes legal entry easier, but the small market makes commercial entry unattractive. A manufacturer can face little legal risk and still reject the product because expected sales do not justify development and ongoing maintenance costs.

What licensing deals or acquisitions involve ethotoin?

No major recent licensing transaction, acquisition or co-development program centered on ethotoin is publicly established. The product lacks the characteristics that typically attract licensing capital:

• No active patent estate.
• No growing indication.
• No premium pricing.
• No specialty formulation.
• No meaningful clinical-development program.
• No visible revenue platform.

If ethotoin changes ownership, the transaction would more likely involve a broader portfolio of legacy medicines than a standalone strategic acquisition. Its value would be based on product continuity, manufacturing rights and residual cash flow rather than pipeline potential.

What generic launch scenarios exist for ethotoin?

Three generic-launch scenarios are commercially plausible.

No new entrant

This is the most likely outcome where current demand is too low to support an additional manufacturer. Existing supply, if available, may continue through a legacy-product holder.

Single niche entrant

A small generic company could enter to address continuity-of-care demand. The entrant would need to secure supply and accept low volume. Pricing could remain unstable because one manufacturer may serve most of the remaining market.

Supply-driven re-entry

A manufacturer could reintroduce ethotoin after a shortage or discontinuation if physicians and patients require an alternative. Such a launch would address supply continuity rather than create new demand.

A large generic launch with substantial volume growth is unlikely. The product has no clear mechanism for recovering mainstream epilepsy market share.

What is the geographic coverage of ethotoin?

Ethotoin’s commercial presence is fragmented by country. Historical approval in one jurisdiction does not establish current marketing in another. Older antiseizure medicines may remain available through national formularies, hospital procurement systems or local licensees even after withdrawal from larger markets.

The United States is the most commercially relevant reference market for FDA and Orange Book analysis, but it is not sufficient to establish global availability. In Europe and other regions, supply depends on local authorization, national reimbursement and manufacturer participation. There is no broad global commercial platform comparable with widely used antiseizure medicines.

What is the investment and business-development outlook?

Ethotoin has low attractiveness for conventional pharmaceutical investment. A buyer would acquire a shrinking maintenance product, not a growth asset. The strongest potential rationale would be portfolio consolidation, continuity of supply or access to a niche legacy-medicine customer base.

The product has limited value in:

• Brand acquisition.
• Specialty-pharma platform building.
• Patent monetization.
• Licensing for international expansion.
• Clinical development.
• Combination-product development.

Its value could be higher during a temporary shortage, but that would be a supply event, not evidence of durable market expansion.

Key Takeaways

• Ethotoin is a legacy hydantoin anticonvulsant historically marketed as Peganone.
• Its principal indications were tonic-clonic and psychomotor seizures.
• The original patent estate is expired and does not create meaningful current exclusivity.
• Orange Book or historical FDA records should not be treated as proof of active commercial availability.
• Paragraph IV litigation risk is low because there is no major branded revenue pool or active high-value patent estate.
• No public source reports meaningful standalone ethotoin revenue.
• The financial trajectory is long-term decline, with any remaining sales tied to legacy patients and supply continuity.
• Generic entry is legally feasible but commercially unattractive because the market is small and fixed regulatory costs are high.
• No significant current licensing, acquisition or co-development activity is publicly associated with ethotoin.
• Ethotoin has no biosimilar risk because it is a small-molecule drug, not a biologic.

FAQs

Is ethotoin still available in the United States?

Ethotoin has limited or uncertain current U.S. commercial availability. Historical FDA approval and labeling do not establish that a product is actively manufactured or distributed.

Is Peganone the same as ethotoin?

Yes. Peganone was the principal historical brand associated with ethotoin tablets.

Can a company launch a generic version of ethotoin?

In principle, yes, because the original compound and product patents are expired. Commercial entry depends on reference-product requirements, manufacturing feasibility, market demand and regulatory maintenance costs.

Is ethotoin more valuable as a rare-disease drug?

No. Ethotoin is an old antiseizure medicine and does not have the development profile, pricing structure or exclusivity framework associated with modern rare-disease products.

Does ethotoin have future revenue growth potential?

The available commercial evidence supports a maintenance or decline scenario rather than growth. Any temporary revenue increase would most likely result from a supply disruption affecting alternatives.

References

1. U.S. Food and Drug Administration. (n.d.-a). Peganone label: Ethotoin tablets. Drugs@FDA. https://www.accessdata.fda.gov/scripts/cder/daf/

2. U.S. Food and Drug Administration. (n.d.-b). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/

3. National Library of Medicine. (n.d.). Ethotoin. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. https://www.ncbi.nlm.nih.gov/books/

4. National Library of Medicine. (n.d.). Ethotoin drug information. MedlinePlus. https://medlineplus.gov/druginfo/meds/

5. U.S. Food and Drug Administration. (n.d.-c). Drug products discontinued from marketing. https://www.fda.gov/drugs/drug-approvals-and-databases/drugsfda-data-files pose