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IMIPRAMINE HYDROCHLORIDE Drug Patent Profile
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Which patents cover Imipramine Hydrochloride, and what generic alternatives are available?
Imipramine Hydrochloride is a drug marketed by Novartis, Chartwell, Leading, Lederle, Oxford Pharms, Par Pharm, Roxane, Sandoz, Specgx Llc, Strides Pharma Intl, Sun Pharm Industries, Teva, Usl Pharma, Vangard, Watson Labs, and West Ward. and is included in thirty-six NDAs.
The generic ingredient in IMIPRAMINE HYDROCHLORIDE is imipramine hydrochloride. There are thirty-four drug master file entries for this compound. Twelve suppliers are listed for this compound. Additional details are available on the imipramine hydrochloride profile page.
DrugPatentWatch® Litigation and Generic Entry Outlook for Imipramine Hydrochloride
A generic version of IMIPRAMINE HYDROCHLORIDE was approved as imipramine hydrochloride by STRIDES PHARMA INTL on October 21st, 1983.
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Questions you can ask:
- What is the 5 year forecast for IMIPRAMINE HYDROCHLORIDE?
- What are the global sales for IMIPRAMINE HYDROCHLORIDE?
- What is Average Wholesale Price for IMIPRAMINE HYDROCHLORIDE?
Summary for IMIPRAMINE HYDROCHLORIDE
| US Patents: | 0 |
| Applicants: | 16 |
| NDAs: | 36 |
| Finished Product Suppliers / Packagers: | 12 |
| Raw Ingredient (Bulk) Api Vendors: | 98 |
| Clinical Trials: | 57 |
| Patent Applications: | 2,355 |
| DailyMed Link: | IMIPRAMINE HYDROCHLORIDE at DailyMed |
Recent Clinical Trials for IMIPRAMINE HYDROCHLORIDE
Identify potential brand extensions & 505(b)(2) entrants
| Sponsor | Phase |
|---|---|
| VA Office of Research and Development | PHASE2 |
| Menoufia University | NA |
| Sohag University | NA |
Pharmacology for IMIPRAMINE HYDROCHLORIDE
| Drug Class | Tricyclic Antidepressant |
Anatomical Therapeutic Chemical (ATC) Classes for IMIPRAMINE HYDROCHLORIDE
US Patents and Regulatory Information for IMIPRAMINE HYDROCHLORIDE
| Applicant | Tradename | Generic Name | Dosage | NDA | Approval Date | TE | Type | RLD | RS | Patent No. | Patent Expiration | Product | Substance | Delist Req. | Exclusivity Expiration |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Watson Labs | IMIPRAMINE HYDROCHLORIDE | imipramine hydrochloride | TABLET;ORAL | 085875-001 | Approved Prior to Jan 1, 1982 | DISCN | No | No | ⤷ Start Trial | ⤷ Start Trial | ⤷ Start Trial | ||||
| Sun Pharm Industries | IMIPRAMINE HYDROCHLORIDE | imipramine hydrochloride | TABLET;ORAL | 081050-001 | Jun 5, 1990 | AB | RX | No | No | ⤷ Start Trial | ⤷ Start Trial | ⤷ Start Trial | |||
| Watson Labs | IMIPRAMINE HYDROCHLORIDE | imipramine hydrochloride | TABLET;ORAL | 085877-001 | Approved Prior to Jan 1, 1982 | DISCN | No | No | ⤷ Start Trial | ⤷ Start Trial | ⤷ Start Trial | ||||
| >Applicant | >Tradename | >Generic Name | >Dosage | >NDA | >Approval Date | >TE | >Type | >RLD | >RS | >Patent No. | >Patent Expiration | >Product | >Substance | >Delist Req. | >Exclusivity Expiration |
Imipramine Hydrochloride Market Dynamics and Financial Trajectory
Imipramine hydrochloride is a mature, off-patent tricyclic antidepressant with limited commercial growth potential. Its market is driven by low-cost generic supply, residual use in major depressive disorder, and niche use in pediatric enuresis. The product has no meaningful new-drug exclusivity, no biosimilar exposure, and limited patent-based barriers to entry. Financial performance is likely stable to declining at the molecule level, with revenue concentrated among generic manufacturers and distributors rather than a branded innovator.
What is the current market position of imipramine hydrochloride?
Imipramine hydrochloride is an oral tricyclic antidepressant marketed primarily as a generic product. The historical reference brand is Tofranil, which was developed by Geigy and later associated with Novartis. Tofranil is no longer a major branded commercial product in the United States.
The FDA-approved product has been used for:
- Major depressive disorder
- Childhood nocturnal enuresis in certain labeling
- Other psychiatric uses in some non-U.S. markets
Imipramine inhibits the reuptake of norepinephrine and serotonin. Its anticholinergic, antihistaminic and cardiac effects limit use relative to newer antidepressants. Safety concerns include overdose toxicity, arrhythmias, orthostatic hypotension, seizures and interactions with monoamine oxidase inhibitors.
The commercial product is generally available as immediate-release tablets in low-dose strengths, including 10 mg, 25 mg and 50 mg, with additional strengths depending on manufacturer and market. FDA labeling identifies imipramine hydrochloride tablets as prescription products rather than over-the-counter medicines.[1]
| Market attribute | Imipramine hydrochloride |
|---|---|
| Therapeutic class | Tricyclic antidepressant |
| Primary dosage form | Immediate-release oral tablets |
| U.S. reference brand | Tofranil |
| Current U.S. commercial model | Generic multisource supply |
| Controlled-substance status | Not federally scheduled |
| Patent-driven exclusivity | Expired |
| New chemical entity exclusivity | Expired |
| Biosimilar relevance | None |
| Main commercial pressure | Substitution by newer antidepressants and low generic pricing |
How large is the imipramine hydrochloride market?
Public companies do not generally report imipramine hydrochloride revenue as a separate product line. The drug is usually grouped within broader generic pharmaceutical, hospital-product or mature-brand portfolios. Publicly available FDA data do not provide a reliable molecule-level market value, unit volume or manufacturer-by-manufacturer revenue estimate.
The commercial market is therefore best characterized by structure rather than a verified dollar figure:
- Demand is mature and relatively predictable.
- Unit prices are low compared with patented antidepressants.
- Several generic suppliers can compete for the same prescriptions.
- Prescription volume is constrained by clinical substitution.
- Net revenue is sensitive to reimbursement and supply conditions.
The historical decline of tricyclic antidepressants reflects the expansion of selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors and newer agents. Imipramine retains clinical utility, but it is not a first-line antidepressant for most patients because of tolerability and overdose concerns.
Its enuresis use creates a smaller but distinct demand segment. Desmopressin, behavioral interventions and alarm systems compete in that indication. The enuresis segment does not compensate for the broader decline in tricyclic antidepressant use.
What is the financial trajectory for imipramine hydrochloride?
The financial trajectory is mature, low-growth and structurally deflationary.
Historical phase
Imipramine generated substantially higher economic value when Tofranil was protected by brand recognition, physician familiarity and historical market exclusivity. That period ended after patent and regulatory exclusivities expired and generic manufacturers entered.
Generic expansion phase
After generic entry, price competition reduced the branded product’s economic value. Generic manufacturers gained access to a clinically established molecule without funding the original discovery program. Distributor purchasing and pharmacy-benefit contracting shifted value toward scale, manufacturing reliability and supply-chain execution.
Current phase
The current market likely produces recurring but modest revenue for suppliers with approved manufacturing capacity. Financial performance depends on:
- Product availability
- API procurement costs
- Manufacturing utilization
- Contracting terms
- Pharmacy reimbursement
- Hospital and retail channel mix
- Competitor withdrawals
- Temporary shortages
The product’s low average selling price limits the upside from volume growth. A manufacturer can improve returns through operational efficiency or temporary supply disruption among competitors, but sustained pricing power is unlikely without a significant reduction in the supplier base.
| Financial driver | Current effect |
|---|---|
| Patent expiry | Eliminates premium pricing |
| Generic competition | Compresses gross margin |
| Stable clinical demand | Supports recurring baseline volume |
| Declining first-line use | Limits long-term growth |
| Low manufacturing complexity | Encourages supplier entry |
| API or finished-dose shortages | Can create temporary price increases |
| Limited brand promotion | Reduces commercial overhead but also limits differentiation |
| Reimbursement pressure | Reduces net realized price |
No reliable public source identifies current annual sales for imipramine hydrochloride as a standalone molecule. Any precise market-size estimate should be treated as a private data-vendor estimate rather than a disclosed financial fact.
When did imipramine hydrochloride lose exclusivity?
Imipramine hydrochloride lost meaningful U.S. exclusivity decades ago. The molecule was introduced in the late 1950s, and its original composition, use and formulation protections are no longer commercially relevant.
The FDA Orange Book identifies approved drug products and any applicable patent or exclusivity information submitted for those products.[2] For a mature generic such as imipramine hydrochloride, the relevant commercial conclusion is that market access is governed by abbreviated new drug application approval, manufacturing capability and reimbursement rather than a surviving innovator patent.
| Exclusivity category | Current position |
|---|---|
| Original drug patent | Expired |
| New chemical entity exclusivity | Expired |
| Pediatric exclusivity | No current commercial significance |
| Orphan exclusivity | Not applicable |
| Reference-product exclusivity | Expired |
| Generic approval pathway | ANDA-based |
| Current patent barrier | No material barrier expected |
The relevant issue is not the expiry of one remaining patent. It is whether a supplier can maintain an approved, economically viable product in a low-price market.
What patents protect imipramine hydrochloride today?
No commercially meaningful patent estate is associated with the core imipramine hydrochloride molecule in the United States. Original compound and early formulation patents are expired.
Potentially relevant rights could still arise from:
- A novel extended-release formulation
- A specialized delivery system
- A new combination product
- A manufacturing process
- A device or packaging configuration
- A newly approved method of use
Those categories do not appear to define the mainstream imipramine hydrochloride tablet market. Standard immediate-release tablets are mature products with limited scope for defensible innovation.
Are formulation patents commercially important?
Formulation patents are not a major current market factor for standard imipramine hydrochloride tablets. The product is chemically stable, orally administered and manufactured using conventional solid-dose technology.
A company seeking differentiated economics would need to develop a formulation with a clinically meaningful advantage, such as improved tolerability, modified release or reduced dosing frequency. Such a strategy would require new clinical, regulatory and commercial investment. The existing low-cost generic market would make return on investment difficult to establish.
Are method-of-use patents relevant?
Method-of-use patents could theoretically cover a new patient population, dosing regimen or therapeutic indication. They would not ordinarily prevent generic manufacturers from selling the conventional product for unpatented uses.
Any such patent would need to withstand validity, written-description, enablement and obviousness challenges. No current method-of-use patent is a central commercial constraint for the established imipramine hydrochloride market.
What is the FDA regulatory status of imipramine hydrochloride?
Imipramine hydrochloride is an FDA-approved prescription medicine. Generic versions are approved through ANDAs that demonstrate pharmaceutical equivalence and bioequivalence to the relevant reference product.
FDA labeling identifies warnings associated with antidepressant use, suicidality in pediatric and young adult patients, cardiovascular effects, seizures, anticholinergic reactions and overdose toxicity.[1] These safety considerations affect prescribing patterns and commercial demand.
The regulatory pathway is comparatively straightforward for a conventional immediate-release tablet, but approval does not guarantee commercial success. Generic manufacturers must maintain compliance with:
- Current good manufacturing practices
- Product quality specifications
- Stability requirements
- Labeling obligations
- Pharmacovigilance requirements
- FDA inspection standards
A manufacturer with an approved ANDA can face commercial pressure if wholesalers or pharmacies prefer another supplier, even when the product remains fully approved.
What is the Orange Book status of imipramine hydrochloride?
The Orange Book is the primary FDA reference for approved drug products, therapeutic equivalence evaluations and listed patent or exclusivity information. Imipramine hydrochloride tablets are generic prescription products evaluated through the FDA’s multisource-drug framework.[2]
The commercial implications are:
- Generic manufacturers can compete without obtaining a license from the historical innovator.
- There is no active brand exclusivity that blocks additional ANDA approvals.
- Standard tablet products generally receive an AB therapeutic-equivalence rating when FDA criteria are met.
- Substitution and reimbursement are shaped by state law, payer policy and pharmacy contracts.
The Orange Book does not provide product-level revenue or market-share data. It also does not eliminate the need to review individual ANDA status, discontinuation records and current supplier availability.
Are there Paragraph IV challenges involving imipramine hydrochloride?
Paragraph IV litigation is unlikely to be commercially material for conventional imipramine hydrochloride tablets because the original exclusivity period ended long ago and the market is already generic.
A Paragraph IV certification is most relevant when an ANDA applicant challenges an unexpired patent listed for a reference product. For a legacy molecule with no meaningful active patent estate, the usual regulatory pathway is not a high-value patent challenge but a standard ANDA submission.
| Litigation issue | Commercial assessment |
|---|---|
| Paragraph IV risk | Low |
| Innovator patent enforcement | Low |
| Formulation patent disputes | Possible in theory, not central to standard tablets |
| Product liability exposure | More relevant than patent litigation |
| Antitrust exposure | Low absent coordinated conduct or supply manipulation |
| Settlement economics | Limited because no major exclusivity prize remains |
No major current settlement agreement is a recognized driver of the imipramine hydrochloride market. Any historical generic settlement would have little effect on current market structure unless it contained unusual manufacturing, supply or distribution restrictions.
Which companies compete in the imipramine hydrochloride market?
Competition comes from generic manufacturers and contract suppliers rather than from actively promoted branded companies. FDA product databases and DailyMed identify approved labels and participating manufacturers, but supplier participation can change through discontinuations, acquisitions and portfolio rationalization.[1][3]
The competitive landscape includes:
- U.S. generic manufacturers with approved ANDAs
- Foreign manufacturers supplying API or finished tablets
- Contract manufacturing organizations
- Wholesaler-owned or private-label generic businesses
- Regional suppliers serving institutional channels
The market does not require sophisticated biologics manufacturing or proprietary delivery technology. The principal barriers are regulatory compliance, validated production, reliable API sourcing and sufficient commercial scale.
How does imipramine compare with newer antidepressants?
| Factor | Imipramine hydrochloride | SSRIs and SNRIs |
|---|---|---|
| Patent position | Expired | Varies by molecule, mostly generic for older products |
| Tolerability | Generally less favorable | Generally more favorable |
| Overdose risk | Higher | Usually lower |
| First-line use | Limited | Common |
| Generic price | Low | Low for mature products |
| Prescriber familiarity | Established but declining | Broad |
| Pediatric enuresis role | Historical niche | Limited or indication-dependent |
| Commercial growth | Low | Depends on molecule and indication |
Imipramine can remain clinically relevant despite weak commercial growth. Prescribing is supported by historical evidence, physician experience and availability of low-cost tablets. Those factors support a baseline market but do not create pricing power.
What manufacturing and supply-chain barriers affect the market?
Manufacturing barriers are moderate at the regulatory level and low at the technology level.
The active pharmaceutical ingredient is a conventional small molecule. Finished-dose production does not require sterile processing, cell culture or complex device assembly for standard tablets. As a result, production can be transferred among qualified generic facilities more readily than production of biologics or complex injectables.
The key risks are:
- Limited API suppliers
- Batch failures
- FDA warning letters or import alerts
- Facility shutdowns
- Low production priority for low-margin products
- Packaging-component shortages
- Wholesaler inventory concentration
- Product discontinuation after margin erosion
A shortage can improve near-term pricing for remaining suppliers, but it can also accelerate substitution to other antidepressants or alternative manufacturers.
What geographic markets offer commercial opportunity?
The United States remains a regulated generic market with limited price upside. Europe and other developed markets also have mature generic competition and national price controls.
Potentially stronger demand may exist in markets where:
- Tricyclic antidepressants remain clinically common
- Generic medicines dominate reimbursement
- Pediatric enuresis treatment options are limited
- Psychiatric care relies on low-cost established medicines
- Local manufacturing or procurement programs favor older products
Geographic expansion would require country-specific registrations, local pharmacovigilance, pricing approvals and supply arrangements. The product’s low unit value makes international expansion attractive only where an existing generic portfolio can absorb regulatory and distribution costs.
Are biosimilars relevant to imipramine hydrochloride?
No. Imipramine hydrochloride is a chemically synthesized small molecule, not a biologic. Biosimilar approval pathways do not apply. Competition occurs through generic drug applications and conventional pharmaceutical-equivalence standards.
This distinction reduces regulatory complexity but also removes the differentiated pricing structure that can exist in certain biologic markets.
What generic launch scenarios exist for imipramine hydrochloride?
The most likely scenarios are operational rather than patent-driven.
Base case
Existing suppliers maintain approvals and compete in a stable, low-price market. Prescription volume gradually declines as newer antidepressants remain preferred. Revenue decreases modestly through lower volume and price pressure.
Supply-consolidation case
One or more manufacturers discontinue the product. Remaining suppliers gain temporary volume and pricing leverage. The effect is limited if other approved suppliers can quickly increase production.
Shortage case
An API or finished-dose disruption creates intermittent availability problems. Hospitals, pharmacies and wholesalers shift orders among suppliers. Revenue may rise for available products, but the effect is episodic rather than structural.
Product-differentiation case
A manufacturer introduces a modified-release or otherwise differentiated formulation. Commercial success would depend on clinical evidence, reimbursement acceptance and protection against rapid generic substitution. This is the least likely near-term scenario because development costs are high relative to the existing market.
What is the investment and licensing outlook?
Imipramine hydrochloride has limited standalone licensing value. A licensing transaction would more likely involve:
- A broader generic portfolio
- Geographic commercialization rights
- A contract manufacturing arrangement
- A hospital or government supply contract
- A reformulated product
- A combination product
A transaction for the conventional tablet alone would generally lack the characteristics of a high-value specialty pharmaceutical deal. The asset has no current branded exclusivity, limited patent leverage and low expected price growth.
For generic manufacturers, the product may still have portfolio value because it uses existing regulatory infrastructure and can generate recurring revenue with limited promotional spending. Its value is greatest as part of a broader psychiatric or mature-products portfolio.
Key Takeaways
- Imipramine hydrochloride is a mature, off-patent generic tricyclic antidepressant.
- Tofranil’s historical brand economics have largely disappeared.
- No material active patent or exclusivity barrier is expected to restrict generic competition.
- The market has recurring demand but limited growth and weak pricing power.
- Major commercial competitors are newer antidepressants, especially SSRIs and SNRIs, rather than patented alternatives.
- Pediatric enuresis provides a niche demand segment, with desmopressin and non-drug interventions as important alternatives.
- Financial performance is driven by manufacturing reliability, reimbursement and supply concentration.
- Biosimilar risk is irrelevant because imipramine is a small-molecule drug.
- Paragraph IV litigation and patent settlements are unlikely to shape current market access.
- Standalone molecule-level revenue is not publicly disclosed by major manufacturers, so precise market-size claims are not supportable from public regulatory filings.
FAQs
Is imipramine hydrochloride still commercially available?
Yes. FDA-approved generic imipramine hydrochloride products have been marketed as prescription tablets, although manufacturer participation and availability can change.
Is imipramine hydrochloride a first-line antidepressant?
Usually not. Newer antidepressants are commonly preferred because imipramine has greater anticholinergic, cardiovascular and overdose-related risks.
Can a new company obtain approval for generic imipramine hydrochloride?
Yes, subject to FDA ANDA requirements, product quality standards, bioequivalence requirements and manufacturing compliance.
Does imipramine hydrochloride have orphan-drug or pediatric exclusivity?
No current exclusivity of that type is a meaningful commercial barrier for the established generic tablet market.
Could a new imipramine formulation command premium pricing?
Potentially, but only if it provides a clinically meaningful benefit and obtains regulatory and reimbursement support. A new formulation would face substantial commercial pressure from inexpensive immediate-release generics.
References
-
U.S. Food and Drug Administration. (n.d.). Imipramine hydrochloride tablets: Prescribing information. DailyMed. https://dailymed.nlm.nih.gov/dailymed/
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U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/
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National Library of Medicine. (n.d.). DailyMed: Current medication labeling. https://dailymed.nlm.nih.gov/dailymed/
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