AMRIX Drug Patent Profile

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

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 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
Finished Product Suppliers / Packagers:	11
Raw Ingredient (Bulk) Api Vendors:	94
Patent Applications:	1,456
Drug Prices:	Drug price information for AMRIX
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for AMRIX
What excipients (inactive ingredients) are in AMRIX?	AMRIX excipients list
DailyMed Link:	AMRIX at DailyMed

See drug prices for AMRIX

See drug sales revenues for AMRIX

Pharmacology for AMRIX

Drug Class	Muscle Relaxant
Physiological Effect	Centrally-mediated Muscle Relaxation

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

Expired US Patents for AMRIX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Teva Pharms Intl	AMRIX	cyclobenzaprine hydrochloride	CAPSULE, EXTENDED RELEASE;ORAL	021777-002	Feb 1, 2007	8,877,245
Teva Pharms Intl	AMRIX	cyclobenzaprine hydrochloride	CAPSULE, EXTENDED RELEASE;ORAL	021777-002	Feb 1, 2007	7,820,203
Teva Pharms Intl	AMRIX	cyclobenzaprine hydrochloride	CAPSULE, EXTENDED RELEASE;ORAL	021777-001	Feb 1, 2007	8,877,245
Teva Pharms Intl	AMRIX	cyclobenzaprine hydrochloride	CAPSULE, EXTENDED RELEASE;ORAL	021777-001	Feb 1, 2007	7,387,793

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

Last updated: July 21, 2026

AMRIX (amrix) market dynamics and financial trajectory: pricing, demand drivers, exclusivity, and generic/biosimilar risks

AMRIX (extended-release cyclobenzaprine hydrochloride) is a niche U.S. muscle relaxant with limited addressable population and competitive pressure from cheaper immediate-release cyclobenzaprine and other skeletal muscle relaxants. Financial trajectory is constrained by (1) steady erosion from generics after patent/exclusivity expiry, (2) low payer tolerance for high-cost non-core products, and (3) prescriber preference for cheaper alternatives, particularly where clinical differentiation is minimal. AMRIX’s revenue profile has been driven primarily by U.S. uptake in acute musculoskeletal indications and durability of formulary position during early lifecycle, followed by deceleration as lower-cost generics captured routine prescriptions.

What is AMRIX and what market does it compete in?

AMRIX is an oral extended-release formulation of cyclobenzaprine, a skeletal muscle relaxant used for relief of discomfort associated with acute, painful musculoskeletal conditions. The product sits in a mature therapeutic category where most payers manage costs through step edits, formulary tiering, and substitution to lower-cost generics.

Which competitors pressure AMRIX pricing and volume?

AMRIX competes against:

• Generic immediate-release cyclobenzaprine (lower cost; immediate dosing)
• Other skeletal muscle relaxants (market fragmentation)
• Payer-managed alternatives where payers prefer lower acquisition cost and similar therapeutic intent

How does the extended-release value proposition affect adoption?

Extended-release dosing can support adherence and may reduce daytime dosing frequency versus immediate-release. That said, therapeutic differentiation is typically limited by:

• Broad class substitutability at the formulary level
• Clinician switching behavior when generics lower copays
• Payer scrutiny on non-opioid symptom management products

What is the Orange Book status of AMRIX and when does exclusivity end?

This section requires AMRIX’s FDA listing and associated patent numbers to compute the exclusivity and patent-expiration timeline. Without Orange Book patent and exclusivity data for AMRIX’s specific strengths and dosage forms, the exclusivity end date cannot be stated accurately.

Which patents protect AMRIX (cyclobenzaprine ER) and how strong is the estate?

This section requires a patent-by-patent mapping of AMRIX’s Orange Book-listed patents (composition, formulation, method of use, and manufacturing) and their expiration dates by jurisdiction. Without the underlying patent list and family data, patent strength and launch-risk cannot be quantified.

When do generic entry risks exist for AMRIX under Hatch-Waxman Paragraph IV?

To assess Paragraph IV risk, AMRIX’s FDA ANDA history (including any filed Paragraph IV certifications), litigation triggers, and settlement terms are required. Without ANDA and certification records tied to AMRIX’s listed patents, a credible generic entry risk window cannot be produced.

What patent litigation affects AMRIX or its cyclobenzaprine ER formulation?

A litigation-impact assessment requires docket-level filings (including civil actions, stay orders, settlement dates, and court findings) tied to AMRIX’s Orange Book patents. Without those case records, the litigation landscape cannot be stated with the required specificity.

How does AMRIX compare with immediate-release cyclobenzaprine on payer economics and uptake?

Key commercial dynamic: acquisition cost and substitution

• Immediate-release cyclobenzaprine is typically widely available as a generic.
• Payers and pharmacy benefit managers can drive substitution through formulary tiering and pharmacy-level edits.
• AMRIX’s market position depends on maintaining formulary acceptance despite higher net cost than generic immediate-release.

Key clinical dynamic: adherence vs substitutability

AMRIX’s extended-release schedule can support adherence. In practice, that benefit competes against:

• Lower price of generics
• Broad clinical category substitutability
• Prescriber tendency to default to lower-cost options once coverage changes

What are the main demand drivers for AMRIX and how stable is utilization?

AMRIX demand is driven by:

• U.S. acute musculoskeletal pain visits treated in outpatient settings
• Short-course prescribing patterns common for muscle relaxants
• Formulary accessibility and payer placement

Stability tends to be moderate to low because muscle relaxant utilization is sensitive to:

• Formulary changes
• Competitive pricing
• Shifts in prescriber behavior and guideline emphasis

What manufacturing and formulation constraints shape AMRIX competitiveness?

For an extended-release capsule product, manufacturing risks that can impact generic entry include:

• Proprietary release characteristics that must be matched under bioequivalence
• Control of dissolution profile and robustness across batches
• Extended-release excipient system sensitivity that can increase CMC burden for entrants

A quantified assessment of manufacturing/IP barriers requires the exact formulation patents, CMC disclosures, and approved product specifications.

What is AMRIX’s financial trajectory: revenue trend, margin profile, and cost pressure?

A quantified financial trajectory requires verifiable financial line items such as AMRIX-specific net sales, payer rebates, gross-to-net bridges, and segment reporting. Without audited financial disclosures or normalized selling data by period, this section cannot be accurately completed.

Which companies are likely to capture AMRIX share as generics enter?

This requires ANDA filer lists, likely launch partners, and historic generic behavior for cyclobenzaprine ER products. Without ANDA and approval records, a credible competitive capture scenario cannot be produced.

How do settlement agreements and exclusivity stays influence AMRIX commercial risk?

Assessing settlement impact requires:

• Names of parties to any settlement
• Dates and scope of any market-entry restrictions
• Patent(s) at issue and permitted carve-outs

Without case and settlement documents, the commercial impact cannot be stated.

What does the FDA regulatory status imply for AMRIX lifecycle?

A lifecycle status analysis depends on:

• Current marketing status by strength and dosage form
• Any FDA labeling changes impacting coverage and prescribing
• Approval history, including supplements

Without FDA approval and label chronology, this section cannot be reliably completed.

Key takeaways

• AMRIX operates in a mature skeletal muscle relaxant category with high substitution pressure from cheaper immediate-release cyclobenzaprine and other muscle relaxants.
• Extended-release differentiation can support adherence, but formulary and payer economics typically dominate once generic costs fall.
• Financial trajectory is expected to follow a typical mature branded pattern: early uptake with formulary durability, then revenue deceleration as lower-cost alternatives expand coverage.
• To quantify exclusivity, patent-driven launch risk, ANDA Paragraph IV timing, and litigation-driven barriers, AMRIX’s Orange Book and FDA dossier details are required.

FAQs

1. How does net price erosion typically affect AMRIX net sales after generic cyclobenzaprine enters?
2. What formulary strategies (step edits, prior auth, tier placement) are most effective against AMRIX reimbursement?
3. What bioequivalence factors most often delay extended-release cyclobenzaprine ER generic launches?
4. How do court-ordered stays and settlements change the expected timing of AMRIX generic switches?
5. Which dosage strengths of AMRIX are most exposed to competitive substitution risk?

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References (APA)

1. U.S. Food and Drug Administration. Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations.
2. U.S. Food and Drug Administration. Drugs@FDA.