DESYREL Drug Patent Profile

Which patents cover Desyrel, and what generic alternatives are available?

Desyrel is a drug marketed by Pragma and is included in one NDA. There is one patent protecting this drug.

This drug has thirty-two patent family members in twenty-three countries.

The generic ingredient in DESYREL is trazodone hydrochloride. There are fourteen drug master file entries for this compound. Thirty-seven suppliers are listed for this compound. Additional details are available on the trazodone hydrochloride profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Desyrel

A generic version of DESYREL was approved as trazodone hydrochloride by APOTEX on March 25^th, 1987.

Summary for DESYREL

International Patents:	32
US Patents:	1
Applicants:	1
NDAs:	1
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for DESYREL

US Patents and Regulatory Information for DESYREL

DESYREL is protected by one US patents.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Pragma	DESYREL	trazodone hydrochloride	TABLET;ORAL	018207-001	Approved Prior to Jan 1, 1982		DISCN	Yes	No	8,133,893		Y	Y
Pragma	DESYREL	trazodone hydrochloride	TABLET;ORAL	018207-004	Nov 7, 1988		DISCN	Yes	No	8,133,893		Y	Y
Pragma	DESYREL	trazodone hydrochloride	TABLET;ORAL	018207-002	Approved Prior to Jan 1, 1982		DISCN	Yes	No	8,133,893		Y	Y
Pragma	DESYREL	trazodone hydrochloride	TABLET;ORAL	018207-003	Mar 25, 1985		DISCN	Yes	No	8,133,893		Y	Y

International Patents for DESYREL

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

Country	Patent Number	Title	Estimated Expiration
Argentina	067773
Australia	2008285779
Brazil	PI0814448
Canada	2693095
China	101772490
Cyprus	1115666
Denmark	2178850

DESYREL (trazodone) investment scenario and patent-and-regulatory fundamentals analysis: exclusivity, Orange Book coverage, generic entry risk, and litigation posture

Last updated: July 12, 2026

Executive summary: DESYREL is immediate-release trazodone (marketed by multiple companies over time). The drug’s core patent and regulatory exclusivity are long expired, and the primary investment relevance is no longer “new-market” exclusivity. Returns are driven by (1) current generic penetration and pricing, (2) any incremental defensibility from formulation or dosing-form patent estates filed later, (3) settlement and litigation history affecting near-term generic supply, and (4) manufacturing and labeling constraints tied to FDA ANDA updates. Without contemporaneous Orange Book listing specifics and current DESYREL labeling/marketing holder details, a precise, patent-by-patent expiration and Paragraph IV map cannot be produced.

Which patents protect DESYREL (trazodone) in the US, and when do they expire?

Short answer: Trazodone is an established small-molecule antidepressant with US patent and regulatory exclusivity that is generally outside active exclusivity windows. A defensible, investment-grade patent estate assessment requires Orange Book listing-level data for “DESYREL” and the specific NDA holder(s) for the branded product currently marketed.

What is the typical patent estate structure for branded trazodone?

For older small-molecule antidepressants, the US patent estate typically splits into:

• Active ingredient composition of matter (generally the earliest, now expired).
• Formulation and manufacturing (often later; may still exist in narrow form if filed late).
• Method-of-use (less common for classic indications when early patents are old, but can exist).
• New dosage forms or controlled/modified-release variants (investment relevance depends on whether the branded label corresponds to those variants).

How does patent expiration map to generic supply economics?

Once composition-of-matter protection expires and FDA exclusivities (if any) have lapsed, ANDA entrants can typically file for immediate generic approval unless:

• The branded NDA still lists unexpired formulation/method patents in the Orange Book.
• There are ongoing litigations that trigger 30-month stay or prompt-cause settlements.

For a current investment view, the gating items are:

• Orange Book “listed patents” with unexpired status.
• Litigation dockets tied to Paragraph IV certifications for those patents.
• Whether branded marketing is tied to an NDA with a still-relevant, late-filed listing.

What is the Orange Book status of DESYREL (trazodone) and what generic entry risks exist?

Short answer: DESYREL is a legacy product where the Orange Book status is expected to show no broad, active exclusivity for composition-of-matter. The actionable risk is whether any Orange Book-listed secondary patents are still unexpired and are being enforced through ANDA litigation.

What to look for in Orange Book to quantify generic entry risk

For an investment model, the key fields are:

• NDA number tied to DESYREL
• Dosage form and strength (immediate-release vs variants)
• Listed patents and their:
  • Expiration dates
  • Patent type (drug substance, drug product, method of use)
  • Orange Book listing number and status (active/inactive)

What generic entry scenarios should be modeled for trazodone brands

Three scenarios typically bracket outcomes:

1. No unexpired listed patents: generics supply expands, brand share erodes quickly, pricing compresses.
2. Unexpired formulation/product patents: generics face delay from litigation or carve-outs.
3. Pending settlements / consent judgments: launch is delayed to a settlement date with limited at-risk uncertainty.

Because DESYREL is old, Scenario 1 is the default baseline unless Orange Book shows still-unexpired listings for the branded NDA.

When does DESYREL (trazodone) lose exclusivity in the US under FDA exclusivity rules?

Short answer: The drug is not a near-term exclusivity play. US marketing exclusivity derived from new clinical investigations or exclusivity triggers is generally exhausted for legacy antidepressants.

Which exclusivity types matter for older small molecules

For completeness in an investment thesis, exclusivity is usually evaluated by:

• NCE exclusivity: applies to new chemical entities at approval, not expected for trazodone.
• 3-year exclusivity: for new clinical investigations for an approved indication, formulation, or dosage form.
• 5-year exclusivity: for changes tied to pediatric studies, typically not applicable to legacy entries.

How exclusivity affects pricing power

When exclusivity is lapsed, branded pricing power becomes a function of:

• Brand differentiation (availability, labeling, supply stability)
• Contract purchasing dynamics
• Generic number of suppliers and ability to maintain low-cost production

What patent litigation affects DESYREL (trazodone) and how does it change launch timing?

Short answer: For an investment-grade answer, the analysis must be tied to the specific NDA and its Orange Book-listed patents. Litigation risk changes launch timing via:

• Paragraph IV suit filing
• 30-month stay effect
• Settlement dates and “trigger dates”
• Court decisions on validity or non-infringement

What litigation indicators are most investable

• Whether any ANDA challenges were filed recently for the same branded NDA/label.
• Whether settlements restrict generic entry dates or allow “at-risk” launches.
• Whether appellate outcomes affect enforceability.

What formulations are protected for DESYREL (trazodone), and are there barriers to generic substitution?

Short answer: The primary generic substitution barrier is not “device-like” differentiation, but rather patent-listed formulation/manufacturing claims and any labeling-based differentiation. For trazodone, barrier potential usually concentrates on:

• Specific dosage form manufacturing methods
• Film coating or excipient systems
• Bioavailability-adjusting formulation claims

Immediate-release versus modified-release variants

Investment relevance depends on which product is meant by “DESYREL” in the commercial plan:

• If the brand is immediate-release, generic substitution tends to be easier once the core patent estate is out.
• If the commercial focus is on modified-release, the patent estate may be more active.

How does DESYREL (trazodone) compare with other trazodone products and competitors on market structure?

Short answer: The competitive landscape for trazodone is usually defined by:

• Generic immediate-release trazodone supply
• Potential presence of specific formulations or strength-specific differentiation
• Class competition in antidepressants, but that does not typically protect trazodone’s IP

What “competition” means for investment modeling

Two distinct competitive layers:

1. IP competition: other products using different patents.
2. Supply competition: multiple generic manufacturers of trazodone API and finished dosage forms competing on price.

Because DESYREL is legacy, supply competition dominates.

Which companies market DESYREL (trazodone) today, and where is revenue exposure concentrated?

Short answer: A correct list requires current FDA labeling/NDA marketing holder mapping and Orange Book ties for the specific DESYREL brand presentation. Without those current identifiers, revenue mapping risks inaccuracies.

What an investment model needs to estimate revenue sensitivity

• Share in managed care formularies
• Contract price erosion with generic entrants
• Patient-level persistence (switching behavior in depression treatment)
• Short supply disruptions that can temporarily support brand pricing

How strong is the patent estate for DESYREL (trazodone) and what is the at-risk window for ANDAs?

Short answer: The patent estate for trazodone brands is generally expected to be weak from an exclusivity standpoint, with any remaining value concentrated in narrow formulation or secondary patents. A true strength score requires enumerating Orange Book-listed patents and mapping their remaining life.

Patent strength scoring framework (what matters for returns)

• Remaining time on listed patents
• Claim scope relative to typical generic formulation routes
• Likelihood of injunction (small-molecule composition patents are easier to enforce than broad functional claims)
• Litigation history: outcomes, transfers, consent judgments

Biosimilar risk for DESYREL (trazodone): is it relevant?

Short answer: No. DESYREL is a small-molecule drug (trazodone). Biosimilar risk does not apply.

Commercial outlook: what drives DESYREL (trazodone) pricing, volume, and margin as exclusivity ends?

Short answer: With exclusivity largely exhausted, margin and volume are driven by supply, procurement, and competitive pricing.

Key commercial drivers

• Generic entrants and number of ANDA suppliers
• API cost and manufacturing capacity
• Pharmacy benefit manager contracting and tender outcomes
• Tender-driven pricing compression, especially for older generics with many suppliers
• Stocking behavior during supply disruptions (brand sometimes benefits in the short term)

Key timeline for DESYREL (trazodone) exclusivity and generic entry

A complete timeline requires Orange Book listing-specific dates and current litigation dockets tied to the relevant NDA. Without those listing identifiers and dates, a precise launch-and-expiry chart cannot be constructed.

Key Takeaways

• DESYREL (trazodone) is a legacy small-molecule antidepressant; the investment case typically hinges on generic supply, pricing erosion, and any remaining secondary patent or litigation constraints tied to the exact branded NDA presentation.
• A patent-and-regulatory exclusivity model requires Orange Book listing-level data for “DESYREL” dosage form(s) and the specific NDA currently associated with the marketed brand.
• Biosimilar risk is not relevant to trazodone.
• The most investable near-term variables are ANDA launch timing, settlement-trigger events, and any still-unexpired formulation/product patents that constrain generic entry.

FAQs

1. What Orange Book patents would need to be listed against the DESYREL NDA to block generic substitution?
2. How do Paragraph IV 30-month stay and settlements typically affect immediate-release antidepressant generics like trazodone?
3. Are formulation patents more likely than method-of-use patents to create barriers for generic trazodone?
4. What labeling or dosage-form distinctions (strength, release profile) matter most for generic interchangeability with DESYREL?
5. How should an investor model margin impact for a legacy antidepressant when generic supplier count increases?

References

1. U.S. Food and Drug Administration. Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations.
2. FDA. ANDA Disclosures and Orange Book Patent/Exclusivity Guidance (FDA resources on ANDA and listed patents).
3. FDA. FDA Guidance for Industry: Patent Certifications for ANDAs (30-month stay framework materials).