SILENOR Drug Patent Profile

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

Silenor is a drug marketed by Currax and is included in one NDA. There are sixteen patents protecting this drug and one Paragraph IV challenge.

This drug has sixteen patent family members in four countries.

The generic ingredient in SILENOR is doxepin hydrochloride. There are seven drug master file entries for this compound. Fifty suppliers are listed for this compound. Additional details are available on the doxepin hydrochloride profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Silenor

A generic version of SILENOR was approved as doxepin hydrochloride by MYLAN PHARMS INC on May 13^th, 1986.

Summary for SILENOR

International Patents:	16
US Patents:	16
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	2
Raw Ingredient (Bulk) Api Vendors:	96
Clinical Trials:	2
Patent Applications:	1,481
Drug Prices:	Drug price information for SILENOR
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for SILENOR
What excipients (inactive ingredients) are in SILENOR?	SILENOR excipients list
DailyMed Link:	SILENOR at DailyMed

See drug prices for SILENOR

See drug sales revenues for SILENOR

Recent Clinical Trials for SILENOR

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

Sponsor	Phase
University of Balamand	Phase 4
Henry Ford Hospital	Phase 4
Pernix Theraputics LLC	Phase 4

See all SILENOR clinical trials

Pharmacology for SILENOR

Drug Class

Tricyclic Antidepressant

Paragraph IV (Patent) Challenges for SILENOR

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
SILENOR	Tablets	doxepin hydrochloride	3 mg and 6 mg	022036	2	2010-09-16

US Patents and Regulatory Information for SILENOR

SILENOR is protected by sixteen US patents.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010	AB	RX	Yes	Yes			Y
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010	AB	RX	Yes	Yes
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010	AB	RX	Yes	Yes
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-001	Mar 17, 2010	AB	RX	Yes	No
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010	AB	RX	Yes	Yes
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010	AB	RX	Yes	Yes

Expired US Patents for SILENOR

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-001	Mar 17, 2010
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-002	Mar 17, 2010
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-001	Mar 17, 2010
Currax	SILENOR	doxepin hydrochloride	TABLET;ORAL	022036-001	Mar 17, 2010

International Patents for SILENOR

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

Country	Patent Number	Title	Estimated Expiration
Canada	2687118
Canada	2687124
European Patent Office	2026792
Japan	2009537553
Japan	2009537554
Japan	2013237694

Last updated: July 24, 2026

SILENOR (doxepin) market dynamics and financial trajectory: sales drivers, payer pressure, and exclusivity timeline

Executive summary: SILENOR (doxepin) is a niche, branded prescription sleep product with a long-running commercial history tied to the insomnia franchise and payer formulary access for low-dose doxepin. Market dynamics are dominated by (1) clinician substitution toward other insomnia agents and behavioral sleep treatment, (2) payer step edits and prior authorization in commercial plans, and (3) competitive pressure from branded and generic sleep drugs whose pricing compresses class net pricing. Financial trajectory is typically shaped less by pipeline conversion and more by incremental share changes in targeted insomnia segments, where formulary placement and persistence drive annual sales outcomes.

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How does SILENOR make money and what drives net sales performance?

Core revenue model: SILENOR is sold as a branded, single-ingredient sleep medication (low-dose doxepin) in the U.S. market. The profit-and-loss profile in mature brands like SILENOR is driven by net price (rebates, discounts, copays), access (formulary position), and persistence (patient continuation versus switching).

Key commercial drivers

1. Formulary access and utilization management
   • Pharmacy benefit manager (PBM) enforcement (step therapy, prior authorization, quantity limits) directly affects prescription volume and script persistence.
   • Plans often prefer lower-cost alternatives if they deliver comparable outcomes for sleep maintenance insomnia.
2. Product positioning in insomnia subtypes
   • Low-dose doxepin is used for insomnia characterized by sleep maintenance and/or difficulty maintaining sleep (clinical differentiation matters for formulary labeling and prescriber comfort).
3. Switching risk versus alternatives
   • Clinicians rotate among insomnia options based on adverse-effect tolerance (sedation, next-day impairment concerns), comorbidities, and patient history.
4. Generic and class-wide price compression
   • As the broader insomnia market experiences generic entry and discounting, branded sleep products typically face margin pressure unless protected by strong access and differentiation.
5. Rebate intensity
   • Net-to-gross erosion is usually the main reason branded insomnia sales do not scale with gross script volume. Rebates rise when PBMs add competing generics or cheaper branded options.

What this means for the financial trajectory

• SILENOR’s annual revenue profile in mature years tends to reflect share versus class more than category growth.
• If formulary access weakens, volume falls faster than category declines because insomnia is highly substitutable.

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What market dynamics affect SILENOR versus other insomnia treatments?

Competitive set (practical payer and prescriber substitution view) SILENOR competes against both prescription and OTC-adjacent sleep options. The highest substitution risk comes from insomnia drugs that can be used without the same “special” handling or that have favorable cost positioning.

Main competitive pressure channels

1. Generic substitution
   • Generic sedative-hypnotics and other insomnia agents compress brand pricing and increase payer preference for lower WAC-to-net cost.
2. Branded branded-against-generic strategy
   • Competing brands often respond with access contracts, manufacturer-funded patient programs, and aggressive rebate positioning to maintain coverage.
3. Nonpharmacologic shift
   • Behavioral interventions (CBT-I) gain traction and reduce the addressable population willing to escalate medication use. Even when prescriptions continue, CBT-I adoption can reduce long-term pharmacotherapy persistence.

Class-level pricing dynamics

• Insomnia is a category where PBMs actively manage utilization. Even when a branded product retains coverage, net pricing can erode through rebate escalation.
• This structure makes branded sleep products vulnerable during any period of competitive entry or intensified PBM contracting.

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What is SILENOR’s exclusivity and patent timeline that shapes market share?

Executive answer: SILENOR’s near-to-medium term commercial strength depends on whether remaining U.S. exclusivity or patent coverage protects specific formulation and method-of-use space, not on core active ingredient exclusivity.

Exclusivity mechanics that affect branded pricing power

1. Orange Book-listed patents
   • Entry on the FDA Orange Book for SILENOR determines what generics can attempt via Paragraph IV ANDA challenges or design-around strategies.
2. Patent term expiration vs. market protection
   • Even after core patent expiration, secondary patents can delay generic filing or complicate design-around.
3. 30-month stay and settlement outcomes
   • If generics file Paragraph IV certifications, litigation and settlement agreements can extend brand market exclusivity via agreed launch dates.

Commercial impact

• When remaining patents narrow, the market typically shifts quickly toward generics, lowering both volume and net pricing unless the brand retains a differentiated niche.

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What patents protect SILENOR in the U.S. and how many are Orange Book-listed?

Executive answer: A complete assessment requires direct Orange Book patent-by-patent coverage and expiration dates tied to each NDA and dosage form strength. Without that listing data, a defensible count and expiration map cannot be produced.

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Are there Paragraph IV ANDA challenges against SILENOR, and how do they influence timelines?

Executive answer: Paragraph IV challenge activity determines whether SILENOR faces imminent generic entry and whether the brand is protected by litigation or settlement.

How Paragraph IV affects financial trajectory

1. Filing year signals
   • A Paragraph IV filing in a given year can create a step-change risk for subsequent quarters, even before final approval because manufacturing planning often reacts early.
2. Settlement launch design
   • If a settlement locks a generic launch date, the brand often experiences temporary revenue stabilization, then faces a discrete “cliff” around the agreed launch.
3. Design-around outcomes
   • If generics design around formulation or method-of-use patents successfully, revenue erosion can start before the expected launch window.

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What is the Orange Book status of SILENOR and what does it mean for generic entry risk?

Executive answer: Orange Book status defines the legal barriers to generic substitution. For a branded insomnia product, the main financial question is whether remaining listed patents cover the exact marketed dosage form and whether design-around is feasible.

Generic entry risk factors

• Strength-specific protection: if only certain strengths are listed, generic entry can be strength-targeted.
• Patent coverage type: formulation vs. method-of-use vs. polymorph/solid-state.
• Litigation posture: whether patents have been sustained or weakened through court outcomes.

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How does SILENOR compare with Doxepin competitors and other low-dose sleep options?

Executive answer: SILENOR is a branded doxepin-based insomnia option. Market share comparison in insomnia generally turns on formulary placement, copay positioning, and prescriber habits rather than on large efficacy differences.

Comparison dimensions that drive payer adoption

1. Net cost after rebates
   • Brands can retain high placement if net cost stays competitive relative to generics and alternative branded options.
2. Therapeutic fit
   • Dosing simplicity and alignment to insomnia subtype matter in conversion from untreated insomnia to maintenance therapy.
3. Safety and tolerability
   • Payers and prescribers track sedation, impairment, and adverse-effect risk, which can steer treatment selection.

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What does SILENOR’s financial trajectory look like by quarter and year?

Executive answer: For mature branded sleep drugs, the trajectory typically follows one of two paths:

1. Flat to modest decline driven by net pricing pressure and incremental formulary losses; or
2. Step-down cliff around generic entry, with a subsequent stabilization at lower run-rate for whatever remaining branded niche is not substituted.

What to watch in reported results (typical patterns)

• Net sales erosion without volume expansion suggests worsening rebates and higher payer pressure.
• Volume decline with stable net price suggests loss of coverage rather than rebate compression.
• Sudden volume drop with unchanged net price suggests immediate generic substitution or formulary switch.

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What licensing or settlement deals exist that affect SILENOR market exclusivity?

Executive answer: Settlement agreements can extend brand revenues by delaying generic launch or by limiting which strengths are launched.

Key deal mechanics

• Agreed launch date in settlement.
• “Carve-out” limitations by dosage strength or claim scope.
• Payment structure tied to market conditions or patent validity findings.

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How does FDA regulatory status affect SILENOR competition and persistence?

Executive answer: FDA labeling and any post-approval changes can affect prescribing behavior and payer compliance.

Regulatory factors

1. Indication alignment
   • Insomnia indication wording impacts eligibility for prior authorizations.
2. Safety communications
   • Any safety alerts influence prescriber willingness to maintain patients on therapy.
3. Supplements
   • Manufacturing and labeling supplements can affect supply reliability, which affects persistence.

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What generic entry risks exist for SILENOR and how could a launch scenario play out?

Executive answer: Generic entry risk is highest when remaining Orange Book patents expire or when litigation ends with a court outcome that permits ANDA approvals.

Generic launch scenario framework

1. Pre-launch volatility
   • Clinicians may pause new starts as generic readiness increases.
2. Launch quarter
   • Market share usually transfers rapidly, especially where PBMs switch to lowest-cost covered alternatives.
3. Post-launch stabilization
   • The brand persists mainly in restricted cohorts that require specific dosing habits or where payers maintain coverage for formulary management reasons.

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Key Takeaways

• SILENOR’s commercial performance is governed mainly by payer access, rebate intensity, and formulary substitution within insomnia rather than by category growth.
• The financial trajectory for a mature insomnia brand typically shows either gradual net erosion or a discrete step-down around generic entry.
• The decisive determinant of generic entry risk is SILENOR’s U.S. patent and Orange Book coverage by dosage form and claim scope, which governs whether ANDA challenges can delay launch via litigation or settlement.

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FAQs

1) What are the most common payer restrictions that reduce SILENOR utilization?
Step edits, prior authorization, and limits on quantity or duration of therapy.

2) How do rebate dynamics typically affect SILENOR net sales even when prescription volume is stable?
Escalating PBM rebates and discounting in response to competing generics or branded alternatives reduce net price and net sales per prescription.

3) What usually happens to branded insomnia sales after generic doxepin entry?
Volume declines quickly due to formulary substitution, followed by net sales stabilization at a lower branded run-rate.

4) Do method-of-use or formulation patents matter differently for SILENOR generic threats?
Yes. Formulation patents can delay design-around more effectively for a specific dosage form, while method-of-use patents can limit approval unless the generic’s labeling or use guidance avoids the protected method.

5) Which competitors most influence SILENOR formulary retention in managed care?
Lower-cost insomnia alternatives with strong formulary contracting, including generics and branded options that maintain net price competitiveness post-rebates.

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References (APA)

No sources provided in the prompt.

DrugChatter Q&A for SILENOR

When does silenor patent end?
Does medicare cover silenor?