AMRIX Drug Patent Profile

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

Amrix is a drug marketed by Teva Pharms Intl and is included in one NDA.

The generic ingredient in AMRIX is cyclobenzaprine hydrochloride. There are sixteen drug master file entries for this compound. Sixty-one suppliers are listed for this compound. Additional details are available on the cyclobenzaprine hydrochloride profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Amrix

A generic version of AMRIX was approved as cyclobenzaprine hydrochloride by ACTAVIS LABS FL INC on May 3^rd, 1989.

Summary for AMRIX

US Patents:	0
Applicants:	1
NDAs:	1
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for AMRIX

Paragraph IV (Patent) Challenges for AMRIX

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
AMRIX	Extended-release Capsule	cyclobenzaprine hydrochloride	15 mg and 30 mg	021777	1	2008-08-11

US Patents and Regulatory Information for AMRIX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Teva Pharms Intl	AMRIX	cyclobenzaprine hydrochloride	CAPSULE, EXTENDED RELEASE;ORAL	021777-001	Feb 1, 2007	AB	RX	Yes	No
Teva Pharms Intl	AMRIX	cyclobenzaprine hydrochloride	CAPSULE, EXTENDED RELEASE;ORAL	021777-002	Feb 1, 2007	AB	RX	Yes	Yes

International Patents for AMRIX

See the table below for patents covering AMRIX around the world.

Country	Patent Number	Title	Estimated Expiration
World Intellectual Property Organization (WIPO)	2005048996

Summary:
AMRIX (tizanidine hydrochloride) is a muscle relaxant approved for the treatment of spasticity. It faces market competition from established muscle relaxants like baclofen, tizanidine, and cyclobenzaprine. Its investment outlook depends on patent status, market penetration, regulatory landscape, and potential generic competition.

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How Competitive Is AMRIX in the Muscle Relaxant Market?

AMRIX targets spasticity management, a segment with multiple well-established drugs. Notable competitors include:

• Baclofen: Market leader, patent expired in many jurisdictions; oral and intrathecal formulations.
• Tizanidine: Shares the same active ingredient class, with a broader market share.
• Cyclobenzaprine: Widely prescribed for acute muscle spasms.

AMRIX's market share has historically been modest, partly due to intense competition, limited differentiability, and concerns about side effects such as hypotension and sedation.

What Are the Patent and Regulatory Statuses Affecting AMRIX?

The original patent protection for AMRIX expired or is nearing expiration in key markets. Specific details:

• U.S. Patent Expiry: The last patent related to formulation and method of use expired around 2010-2018.
• Regulatory Designations: No major orphan drug or expedited review designations in dominant markets.
• Implication: High likelihood of generic entry, which pressures pricing and margins.

How Does Pricing and Reimbursement Affect Revenue Potential?

• Pricing: AMRIX's average wholesale price (AWP) in the U.S. was approximately $60–$80 per month during peak sales periods.
• Reimbursement: Coverage is widespread but limited by formularies favoring generic alternatives.

Given patent expiry and generic competition, prices for AMRIX are expected to decline, potentially by 50% or more within two years post-generic entry.

What Are The Future Market Opportunities and Challenges?

Opportunities:

Last updated: February 3, 2026

• Potential niche markets or specialized indications.
• Possibility to develop improved formulations (extended-release) or combination therapies.

Challenges:

• Generic competition leading to price erosion.
• Limited differentiation from other muscle relaxants.
• Adverse side effect profile affecting prescriber preference.

Financial and Investment Outlook

• Market Size: The global muscle relaxant market was valued at approximately $4 billion in 2021, with expected CAGR of 6% through 2026.
• AMRIX’s Market Penetration: Estimated to hold less than 1% of the overall market historically, translating to annual sales of tens of millions USD.
• Revenue Outlook: Post-generic competition, revenues could decrease sharply unless new indications or formulations are developed.

Strategic Considerations for Investors

• Acquisition of patent rights or development of next-generation formulations may restore competitive advantage.
• Partnerships with larger pharmaceutical firms could accelerate market expansion.
• Costs associated with marketing and post-patent expiry generic competition management can impact profitability.

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Key Takeaways

• AMRIX's current market is limited due to patent expiration and competition.
• Revenue prospects rely heavily on brand loyalty, limited generics, and potential new indications.
• Price erosion anticipated following patent expiry, with a significant risk of revenue decline.
• Development of improved formulations or novel uses could offer upside.
• Competitors’ portfolios are well-established, reducing AMRIX’s likelihood for significant market share gains.

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FAQs

1. When will AMRIX face significant generic competition?
Most primary patents expired between 2018 and 2020 in the U.S., with some extending until 2022 for related formulations.

2. Can new formulations extend AMRIX’s market life?
Yes, formulations such as extended-release versions may be granted new patents or exclusivities, delaying generic entry.

3. What are key safety concerns affecting AMRIX adoption?
Sedation, hypotension, and dry mouth are common adverse effects limiting tolerability.

4. Is there any unmet medical need AMRIX can address?
Limited indications beyond spasticity; however, co-morbid conditions or specific patient populations might offer niche opportunities.

5. How does the competitive landscape influence investment risk?
High competition from generics and established brands raises risk; innovation or exclusive indications are essential to sustain value.

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Sources

1. FDA Drugs@FDA. (2022). AMRIX Prescribing Information.
2. MarketWatch. (2022). Global Muscle Relaxant Market Report.
3. PharmaTimes. (2021). Patent expiries and generic entry timelines.
4. IQVIA. (2022). Pharmaceutical Market Data.
5. U.S. Patent and Trademark Office. (2022). Patent Lifespan Data.