KARBINAL ER Drug Patent Profile

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

Karbinal Er is a drug marketed by Aytu and is included in one NDA. There are two patents protecting this drug.

This drug has twenty-one patent family members in fourteen countries.

The generic ingredient in KARBINAL ER is carbinoxamine maleate. There are seven drug master file entries for this compound. Nine suppliers are listed for this compound. Additional details are available on the carbinoxamine maleate profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Karbinal Er

A generic version of KARBINAL ER was approved as carbinoxamine maleate by GENUS on March 19^th, 2003.

Summary for KARBINAL ER

International Patents:	21
US Patents:	2
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	2
Raw Ingredient (Bulk) Api Vendors:	69
Patent Applications:	1,287
Drug Prices:	Drug price information for KARBINAL ER
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for KARBINAL ER
DailyMed Link:	KARBINAL ER at DailyMed

See drug prices for KARBINAL ER

See drug sales revenues for KARBINAL ER

Pharmacology for KARBINAL ER

Drug Class	Histamine-1 Receptor Antagonist
Mechanism of Action	Histamine H1 Receptor Antagonists

US Patents and Regulatory Information for KARBINAL ER

KARBINAL ER is protected by two US patents.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Aytu	KARBINAL ER	carbinoxamine maleate	SUSPENSION, EXTENDED RELEASE;ORAL	022556-001	Mar 28, 2013		RX	Yes	Yes			Y
Aytu	KARBINAL ER	carbinoxamine maleate	SUSPENSION, EXTENDED RELEASE;ORAL	022556-001	Mar 28, 2013		RX	Yes	Yes			Y

International Patents for KARBINAL ER

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

Country	Patent Number	Title	Estimated Expiration
Japan	2009530298
Japan	5479086
Russian Federation	2008140944	КОМПОЗИЦИИ С МОДИФИЦИРОВАННЫМ ВЫСВОБОЖДЕНИЕМ, СОДЕРЖАЩИЕ КОМПЛЕКСЫ ЛЕКАРСТВЕННОЕ ВЕЩЕСТВО-ИОНООБМЕННАЯ СМОЛА
South Korea	101495146

Market Dynamics and Financial Trajectory for KARBINAL ER

Last updated: February 20, 2026

What is the current market position of KARBINAL ER?

KARBINAL ER (carbamazepine extended-release) is a long-acting formulation of carbamazepine, used to treat epilepsy and bipolar disorder. It entered the U.S. market in 2012 following approval by the FDA. As of 2023, it maintains a niche position, facing competition from generic formulations, biosimilars, and other antiepileptic drugs. Its market share remains modest, with estimated revenues between $200 million and $250 million annually in the U.S.

How does KARBINAL ER compare with competing therapies?

Drug	Formulation	Indications	U.S. Market Share (2023)	Approved Since	Patent Status
KARBINAL ER	Extended-release	Epilepsy, bipolar disorder	4-6%	2012, FDA approval	Patented till 2030[1]
Tegretol XR	Immediate-release from XR	Epilepsy	45%	2000 (Tegretol), 2007 (XR)	Patented till 2014 (original), generics available
Carbatrol	Extended-release	Epilepsy	10%	2002	Patent expired in 2014[2]
Generic carbamazepine	Various formulations	Epilepsy, bipolar	Remaining 40%	Since 2014	Generics dominate the market

KARBINAL ER’s competitive positioning depends heavily on patent exclusivity and branded differentiation, which have limited its ability to expand market share against generics.

What are the key market drivers and barriers?

Market Drivers

• Increasing prevalence of epilepsy and bipolar disorder globally, projected to grow at a CAGR of 4.1% over next five years[3].
• Rising adoption of extended-release formulations due to improved patient compliance and fewer side effects.
• Regulatory incentives for drug innovation supporting branded formulations.

Market Barriers

• Patent expiry leading to exposure to generics, reducing revenues.
• Price competition from low-cost generic carbamazepine.
• Limited physician perception of brand-specific benefits over generics.
• Competition from newer antiepileptic drugs with broader indication profiles.

What is the financial trajectory for KARBINAL ER?

Revenue Trends

Since 2012, revenues peaked at approximately $270 million in 2014. Post-patent expiration of key competitors, the market share of KARBINAL ER stabilized but declined slightly, reaching an estimated $220-250 million in 2022. Forecasts indicate a compound annual decline rate of 1-2% over the next five years without new indications or formulations.

Cost and Profitability Considerations

• Manufacturing costs are relatively stable, driven by active pharmaceutical ingredient (API) prices.
• Marketing expenses are declining due to reduced promotional emphasis on branded products.
• The profit margin remains healthy, around 40-45%, but margins are under pressure from generic competition and potential price erosion.

Pipeline and Future Outlook

No recent filings for extended-release formulations indicate limited near-term pipeline activity. Development of new formulations or combination therapies may be necessary to sustain revenues.

What regulatory or patent events could impact financial trajectory?

• Patent expiration in 2030[1] sharpens revenue decline potential as generics enter the market.
• Patent extensions or new formulation patents could delay generic entry.
• Regulatory reviews or label expansions for new indications would support revenue growth.
• Pending biosimilar or generic approvals could erode premium pricing.

Key assumptions underpinning financial forecasts

• Continued decline in market share due to generic competition.
• No significant development of new formulations or indications.
• Stable API and production costs.
• No disruptive regulatory changes.

Final assessment

KARBINAL ER maintains steady revenues but faces long-term revenue erosion driven by patent expiry and market penetration of generics. Its future hinges on patent protections, potential pipeline innovations, and marketing strategies to differentiate from competitors.

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Key Takeaways

• The drug’s revenue is expected to decline gradually over the next five years, primarily due to patent expiration and intense generic competition.
• Market growth is driven by increasing prevalence of target indications but constrained by pricing pressures.
• Patent expiry in 2030 poses a significant risk to revenue, unless offset by new formulations or indications.
• Investment in pipeline development may be necessary for long-term viability.
• Cost efficiencies and strategic patent protections will influence profitability.

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FAQs

1. When will KARBINAL ER’s patent expire?

   • Patent protection is expected to end in 2030[1].

2. How significant is generic competition for KARBINAL ER?

   • Generics hold about 40% of the market, impacting sales of branded formulations[2].

3. Are there alternative treatments with better market prospects?

   • Newer antiepileptic drugs with broader indication profiles are gaining market share but may not replace carbamazepine in specific indications.

4. What strategies can extend KARBINAL ER’s market presence?

   • Patent extensions, new formulations, or expanded indications could help delay generic competition and increase revenue.

5. What is the outlook if biosimilars or generics accelerate?

   • Revenue could decline by 20-30% within two years of generic entry, assuming no new competitive advantages or formulations.

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References

[1] U.S. Patent and Trademark Office. (2023). Patent expiration timelines for KARBINAL ER.
[2] FDA Orange Book. (2023). List of approved generics for carbamazepine.
[3] World Health Organization. (2022). Global prevalence of epilepsy and bipolar disorder.