GRISACTIN Drug Patent Profile

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Which patents cover Grisactin, and when can generic versions of Grisactin launch?

Grisactin is a drug marketed by Wyeth Ayerst and is included in four NDAs.

The generic ingredient in GRISACTIN is griseofulvin, ultramicrocrystalline. There are two drug master file entries for this compound. Additional details are available on the griseofulvin, ultramicrocrystalline profile page.

Summary for GRISACTIN

US Patents:	0
Applicants:	1
NDAs:	4
Raw Ingredient (Bulk) Api Vendors:	1
Patent Applications:	4,409
DailyMed Link:	GRISACTIN at DailyMed

US Patents and Regulatory Information for GRISACTIN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Wyeth Ayerst	GRISACTIN	griseofulvin, microcrystalline	CAPSULE;ORAL	050051-002	Approved Prior to Jan 1, 1982		DISCN	No	No
Wyeth Ayerst	GRISACTIN ULTRA	griseofulvin, ultramicrocrystalline	TABLET;ORAL	062438-002	Nov 17, 1983		DISCN	No	No
Wyeth Ayerst	GRISACTIN ULTRA	griseofulvin, ultramicrocrystalline	TABLET;ORAL	062178-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Wyeth Ayerst	GRISACTIN	griseofulvin, microcrystalline	CAPSULE;ORAL	050051-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Wyeth Ayerst	GRISACTIN	griseofulvin, microcrystalline	TABLET;ORAL	060212-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Wyeth Ayerst	GRISACTIN ULTRA	griseofulvin, ultramicrocrystalline	TABLET;ORAL	062178-002	Approved Prior to Jan 1, 1982		DISCN	No	No

Grisactin Market Dynamics and Financial Trajectory: Legacy Griseofulvin Brand Analysis

Last updated: October 15, 2026

Grisactin is a legacy oral griseofulvin brand that has lost commercial relevance in the United States. Its market declined as generic griseofulvin became available, newer oral antifungals entered dermatology, and treatment shifted toward shorter-course therapies. Grisactin does not have a meaningful current standalone revenue stream or active brand-based exclusivity position. The commercial opportunity is concentrated in low-cost generic griseofulvin, not in the Grisactin trademark.

What is Grisactin and which drug does it contain?

Grisactin contains griseofulvin, an oral antifungal used primarily for dermatophyte infections involving the skin, scalp, hair and nails. Griseofulvin is produced by fungi of the Penicillium species and acts by disrupting fungal mitosis.

Historically, Grisactin was marketed in microsize and ultramicrosize oral formulations. The product was available in tablet and oral suspension formats. Griseofulvin microsize and ultramicrosize differ in particle size and absorption characteristics, so dosage strength and formulation cannot be compared solely on a milligram-for-milligram basis.

Product	Active ingredient	Historical use	Current commercial position
Grisactin	Griseofulvin	Oral treatment of dermatophyte infections	Legacy or discontinued brand in the U.S.
Generic griseofulvin microsize	Griseofulvin	Tinea infections, particularly scalp and skin	Generic market
Generic griseofulvin ultramicrosize	Griseofulvin	Oral antifungal therapy	Limited generic market
Gris-PEG	Griseofulvin ultramicrosize	Oral antifungal therapy	Separate brand; not interchangeable with Grisactin without dosage review

The U.S. product most frequently confused with Grisactin is Gris-PEG. Gris-PEG is a separate griseofulvin brand associated with ultramicrosize tablets. A historical Grisactin prescription should not be assumed to be therapeutically or commercially identical to Gris-PEG.

When did Grisactin lose exclusivity?

Grisactin lost practical market exclusivity many years ago. Its original composition and formulation protection are long past the effective commercial life expected for a modern pharmaceutical brand.

The product’s economic decline resulted from three factors:

1. Generic griseofulvin became available.
2. The underlying active ingredient became clinically mature and inexpensive.
3. Alternative antifungals, including terbinafine and azole products, captured prescribing in several dermatologic indications.

There is no current evidence that Grisactin retains a live U.S. patent or regulatory exclusivity period capable of supporting premium pricing. FDA Orange Book patent and exclusivity protections are generally relevant to currently marketed NDA products. A legacy product that is no longer marketed does not retain economic protection merely because its historical NDA remains in FDA records. [1]

Estimated exclusivity timeline

Period	Commercial event	Financial effect
Historical launch period	Grisactin introduced as branded oral griseofulvin	Brand pricing and physician recognition
Generic entry period	Generic griseofulvin becomes available	Rapid price compression
Later lifecycle period	Alternative antifungals expand use	Reduced prescription share
Current period	Brand becomes legacy or discontinued	Little or no branded revenue

An exact Grisactin patent-expiration date is not commercially material because the relevant protection expired decades ago or ceased to have practical value before the current generic market developed. The available public record does not support a current Grisactin-specific patent blocking generic entry.

What is the FDA regulatory status of Grisactin?

Grisactin is not a major active U.S. branded product in current FDA commercial practice. FDA drug databases distinguish among marketed, discontinued and withdrawn products. A discontinued listing does not by itself establish that FDA withdrew the product for safety or efficacy reasons. It indicates that the product is no longer marketed under the relevant listing or is otherwise no longer active in the commercial distribution system. [1]

Current FDA regulatory relevance rests with generic griseofulvin products rather than Grisactin. Generic applicants may rely on the established safety and efficacy of the reference drug through the abbreviated new drug application pathway, subject to applicable FDA requirements.

The current regulatory market is therefore defined by:

• Generic griseofulvin tablets.
• Generic oral suspension where available.
• Formulation-specific manufacturing controls.
• Bioequivalence and pharmaceutical-equivalence requirements.
• Labeling requirements for dermatophyte infections.

What patents protect Grisactin and generic griseofulvin?

No active Grisactin patent estate appears to provide a meaningful barrier to generic entry. The relevant historical patent categories would have included:

Patent category	Historical relevance	Current barrier
Active-ingredient patents	Griseofulvin was discovered and commercialized decades ago	None of practical significance
Particle-size patents	Could distinguish microsize or ultramicrosize products	Historical protection is expired or commercially weak
Formulation patents	Could cover suspension or tablet composition	No apparent current Grisactin barrier
Method-of-use patents	Could cover treatment of fungal infections	No meaningful brand exclusivity
Manufacturing patents	Could cover particle processing or dosage manufacture	Possible process know-how, but not a Grisactin market block

The principal remaining intellectual-property value is manufacturing know-how. Particle-size control, dissolution behavior, stability and suspension uniformity can affect product quality, but these factors do not recreate brand exclusivity. A generic manufacturer may design around a historical process claim or use a different validated manufacturing route.

How strong is the Grisactin patent estate?

The Grisactin patent estate is commercially weak to nonexistent as a current exclusivity platform.

Its strength can be assessed across four dimensions:

Criterion	Assessment
Composition-of-matter protection	Expired
Formulation protection	Historical and unlikely to block current generic products
Method-of-use protection	No meaningful current commercial impact
Manufacturing protection	Potentially relevant to cost and quality, but not market exclusivity

Griseofulvin is a mature small molecule. It has no biologic complexity, no biosimilar pathway and no modern platform patent structure. The principal competitive variables are manufacturing cost, supply reliability, regulatory compliance, wholesaler access and formulary placement.

What is the competitive landscape for griseofulvin?

Griseofulvin competes against both generic versions of the same molecule and alternative antifungals.

Competitor	Drug class	Competitive position
Generic griseofulvin	Oral antifungal	Direct substitute for Grisactin
Terbinafine	Allylamine antifungal	Strong competitor, particularly for dermatophyte infections
Fluconazole	Triazole antifungal	Used in selected fungal infections
Itraconazole	Triazole antifungal	Used where broader antifungal coverage is required
Topical azoles	Topical antifungals	Compete in superficial infections
Topical terbinafine	Topical allylamine	Competes in uncomplicated skin disease

Griseofulvin retains clinical utility in tinea capitis, especially in pediatric treatment and infections caused by Microsporum species. Its limitations include longer treatment duration, variable absorption, drug-interaction considerations and the need to administer some formulations with dietary fat to improve absorption.

Terbinafine has taken share in several dermatophyte indications because of shorter treatment courses and strong activity against Trichophyton species. Clinical selection remains dependent on infection site, organism, patient age, liver considerations and local practice patterns. [2][3]

What is the financial trajectory for Grisactin?

The financial trajectory is a classic branded-drug erosion curve:

1. Initial branded sales were supported by product recognition and limited competition.
2. Generic entry reduced price and prescription value.
3. Newer antifungals reduced demand in selected indications.
4. The brand lost distribution and commercial visibility.
5. Current value shifted from Grisactin to generic griseofulvin manufacturing.

No reliable public source reports current standalone Grisactin revenue. The brand is not a separately disclosed product in major public-company financial reporting, and generic griseofulvin sales are generally aggregated across manufacturers. Any precise current Grisactin revenue estimate would therefore be unsupported.

Revenue exposure

Revenue category	Current exposure
Grisactin branded sales	Minimal or unavailable
Generic griseofulvin sales	Low-value, fragmented market
Hospital or institutional demand	Limited but recurring
Pediatric dermatology demand	Clinically relevant
Specialty pharmacy economics	Not material
Licensing value	Low
M&A value	Low unless tied to a broader generic portfolio

The market can generate recurring unit demand without producing meaningful brand economics. Volume persistence should not be confused with pricing power.

Which companies are challenging Grisactin?

There is no important current Paragraph IV challenge directed at Grisactin as a commercially protected brand. The competitive challenge occurred through ordinary generic entry and substitution rather than an active litigation campaign.

Paragraph IV litigation is generally relevant when a generic applicant challenges an unexpired listed patent for a marketed reference product. Grisactin’s age and lack of meaningful current patent protection make a new Paragraph IV event commercially unlikely. FDA patent-listing and exclusivity data should be checked against the current Orange Book for any specific NDA or ANDA analysis. [1]

No current biosimilar risk exists. Griseofulvin is a small-molecule drug, not a biologic. The relevant regulatory mechanism is ANDA generic competition, not biosimilar interchangeability.

What generic entry risks exist?

Generic entry risk for any remaining Grisactin-branded demand is effectively complete. The principal business risks have shifted from entry to supply and compliance.

Current market risks

• Low average selling prices.
• Limited manufacturer participation.
• Manufacturing-site disruption.
• Active-pharmaceutical-ingredient supply constraints.
• FDA warning letters or import restrictions.
• Low pharmacy reimbursement.
• Formulation-specific shortages.
• Substitution by terbinafine or azole products.

A manufacturer entering the market would face limited patent risk but potentially difficult economics. Small generic markets can have poor margins because fixed regulatory, quality and distribution costs are spread over modest volumes.

What formulation and manufacturing barriers remain?

Griseofulvin formulation is technically less complex than a biologic or extended-release product, but it is not frictionless.

Relevant manufacturing issues include:

• Control of particle-size distribution.
• Content uniformity.
• Dissolution and absorption performance.
• Suspension sedimentation and redispersibility.
• Stability across shelf life.
• Taste and pediatric acceptability.
• Consistent supply of qualified active ingredient.
• Bioequivalence or equivalent pharmaceutical performance.

Ultramicrosize formulations may provide dose advantages, but they can require different manufacturing controls from microsize products. A manufacturer cannot assume that a generic microsize product is a direct commercial replacement for an ultramicrosize product without evaluating labeling, strength, dosage and pharmacokinetics.

How does Grisactin compare with Gris-PEG?

Attribute	Grisactin	Gris-PEG
Active ingredient	Griseofulvin	Griseofulvin
Historical formulation	Microsize or related historical product presentations	Ultramicrosize tablets
Current brand visibility	Legacy or discontinued	Separate continuing or historical brand depending on market status
Patent value	No meaningful current protection	Limited practical exclusivity for the mature molecule
Generic substitution	Generic griseofulvin products	Must account for formulation and dosage differences
Commercial outlook	Minimal standalone value	Niche brand value, if actively marketed

The commercial comparison is therefore one of legacy brand versus formulation-specific brand positioning. Neither product has the economics of a protected modern specialty drug.

What licensing or settlement agreements affect Grisactin?

No material current licensing deal or settlement agreement is publicly associated with Grisactin that would alter generic access, pricing or exclusivity. The product’s economic history is driven by expiration, generic substitution and therapeutic competition rather than a major patent settlement.

There is also no commercially relevant biosimilar settlement framework because griseofulvin is not a biologic.

Key Takeaways

• Grisactin is a legacy griseofulvin brand with little or no current standalone U.S. commercial value.
• Generic griseofulvin, not Grisactin, defines the current market.
• No meaningful active patent or regulatory exclusivity appears to block generic competition.
• The market has low pricing power and limited revenue potential.
• Griseofulvin remains clinically relevant in selected dermatophyte infections, particularly tinea capitis.
• Terbinafine and azole antifungals constrain growth.
• Manufacturing know-how may affect quality and cost but does not create durable brand exclusivity.
• There is no meaningful current Paragraph IV, biosimilar or patent-settlement risk associated with Grisactin.
• Any investment thesis would depend on portfolio economics, supply reliability or niche formulation positioning rather than Grisactin brand equity.

FAQs About Grisactin Market Value and Exclusivity

Is Grisactin still sold in the United States?

Grisactin is generally treated as a legacy or discontinued U.S. brand. Current prescribing and dispensing activity is centered on generic griseofulvin products and separate griseofulvin brands where available.

Is Grisactin the same as Gris-PEG?

No. Both contain griseofulvin, but Gris-PEG is associated with an ultramicrosize formulation. Dosage and formulation substitution require product-specific review.

Does Grisactin have an active patent?

No meaningful current Grisactin patent protection is apparent from the mature age of the product and the availability of generic griseofulvin. Historical formulation or manufacturing patents do not appear to provide a current market block.

Can a company launch a generic version of Grisactin?

A company can pursue an FDA-approved generic griseofulvin product if it satisfies applicable pharmaceutical-equivalence, bioequivalence, quality and manufacturing requirements. Commercial returns may be limited by low pricing and modest market size.

Is griseofulvin subject to biosimilar competition?

No. Griseofulvin is a small-molecule drug. Competition proceeds through generic-drug pathways, primarily abbreviated new drug applications, rather than biosimilar applications.

References

1. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book

2. American Academy of Dermatology. (2023). Tinea capitis: Diagnosis and treatment. https://www.aad.org/public/diseases/a-z/ringworm-scalp-treatment

3. World Health Organization. (2023). WHO guidelines for the diagnosis and management of tinea capitis and other dermatophyte infections. World Health Organization.