When do the PROMETHAZINE HYDROCHLORIDE PLAIN patents expire, and when will PROMETHAZINE HYDROCHLORIDE PLAIN go generic?

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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Ani Pharms	PROMETHAZINE HYDROCHLORIDE PLAIN	promethazine hydrochloride	SYRUP;ORAL	008381-004	Apr 18, 1984		DISCN	Yes	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Ani Pharms	PROMETHAZINE HYDROCHLORIDE PLAIN	promethazine hydrochloride	SYRUP;ORAL	008381-003	Approved Prior to Jan 1, 1982		DISCN	Yes	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

Last updated: July 25, 2026

Promethazine Hydrochloride Plain (Promethazine HCl) Investment Scenario and Patent/Regulatory Fundamentals Analysis

Promethazine hydrochloride plain is an established, off-patent antihistamine with long commercial history and broad generic availability. From a modern investment lens, near-term returns depend less on IP exclusivity and more on (1) niche formulation or delivery IP, (2) distribution contracts and channel mix, (3) regulatory defensibility (label positioning and safety/brand controls), and (4) supply-chain reliability for a generic-heavy, price-sensitive market.

Because the drug is widely marketed as an older generic, the core question for investors is not “Is the active ingredient protected?” but “Is there any remaining, enforceable exclusivity around a specific dosage form, strength, or labeling pathway in the target geography?” Without a defined product (e.g., tablet vs suppository vs oral syrup), business cases are typically driven by commercial execution rather than patent cliffs.

What is promethazine hydrochloride plain and what products compete with it?

Promethazine hydrochloride is a first-generation antihistamine used for allergy symptoms, nausea and vomiting, and off-label indications in some markets. “Plain” generally denotes the active ingredient without combination components (as opposed to promethazine + codeine or other fixed-dose combinations in certain jurisdictions).

Common dosage forms and likely competitive set

Promethazine HCl plain is typically sold as multiple generic dosage forms. Market competition usually includes:

Immediate-release tablets/capsules
Oral syrup (liquid)
Injectable solution (where available/approved)
Suppositories
Topical/other forms in some jurisdictions (less common for “plain” labeling)

In most major markets, generic competition is extensive. The economic implication is that pricing power is usually limited to:

Brand remnants (if any legacy brand exists in a local market)
Contract manufacturing relationships
Product availability and pharmacovigilance performance
Differentiated formulation only where exclusivity or bioequivalence friction exists

How do you model investment returns for an off-patent antihistamine like promethazine HCl plain?

For an older antihistamine, a workable investment model usually prices the asset as a manufacturing and distribution business with regulatory constraints, not as a patent-driven platform.

Core value drivers

Unit economics under competitive generics
- Gross margin depends on input costs (API, packaging), scale, and ability to avoid price erosion on tenders.
Regulatory maintenance cost
- Ongoing stability, pharmacovigilance, and periodic product lifecycle updates can outweigh incremental R&D.
Supply chain continuity
- Stock-out risk can be material in hospital tender systems for widely used antiemetics/antihistamines.
Portfolio adjacency
- Investors often underwrite promethazine HCl plain as an add-on within a broader generics/OTC portfolio, rather than as a standalone growth engine.

What typically limits upside

Fast price decline after new generic entry
Limited differentiation without formulation/device exclusivity
Label and safety-driven restrictions that can reduce addressable use in some segments

What patents protect promethazine hydrochloride plain and how many are likely still active?

For promethazine hydrochloride itself, primary compound patents are historically expired in most jurisdictions. The practical IP question is whether any late-cycle patents remain for:

Specific formulations (e.g., controlled-release)
Specific manufacturing processes
Specific particle size or polymorph claims
Specific packaging or stability improvements
Specific method-of-use claims that survived to later filings in a jurisdiction

Investment implication

If the target business case is a standard immediate-release generic tablet/syrup/injection: enforceable patent protection is typically absent.
If the target is a differentiated dosage form (e.g., a novel release profile, stabilized liquid, or specialized unit-dose format): there can be a defendable moat, but that moat belongs to the product concept, not to promethazine HCl as a molecule.

Because “plain” does not specify a dosage form, strength, route of administration, or country, a complete patent estate enumeration is not supportable here. Any defensible investment underwriting must start with the specific product listing and its Orange Book or local equivalent entries.

When does promethazine hydrochloride plain lose exclusivity and what is the typical entry timing?

For older antihistamines, “exclusivity” is usually not a single event but a set of regulatory and reference-product dependencies:

Bioequivalence pathway timing
Market authorization renewals
Any orphan-like designation (rare for antihistamines)
Any data exclusivity for a specific changed formulation (uncommon for plain generics)

Typical generics reality

Entry timing is more constrained by dossier readiness and facility approvals than by exclusivity.
If a jurisdiction has limited reformulation exclusivity, generics can launch quickly once regulatory files are accepted and bioequivalence obligations are met.

Without a defined market and product authorization, a precise exclusivity timeline is not producible at an investment-grade level.

What is the Orange Book status of promethazine hydrochloride plain in the US?

US exclusivity and patent listing status depends on whether a specific NDA with listed patents exists for the “plain” product, and whether that product remains active on the Orange Book.

Promethazine HCl is widely available as generics, implying that:

Many relevant approvals are generic ANDAs without active Orange Book listing for new patents.
Any listing that remains would likely reflect formulation/process patents tied to a specific branded or reference product still listed on the Orange Book.

A full “Orange Book status” requires the exact branded/reference product name, dosage form, strength, and application type. Those details are not provided, so a correct listing and status table cannot be generated.

How strong is the patent estate for promethazine HCl plain versus other antihistamines?

As a category, first-generation antihistamines tend to be:

Structurally old
Heavily genericized
Competitive on cost and availability

In relative terms, patent strength for promethazine HCl plain is typically lower than for:

Newer second-generation antihistamines with modern formulation IP
Fixed-dose combo products with remaining protection in certain geographies
Drugs with recent reformulations or line extensions

Investment positioning should therefore treat IP as secondary unless the target is a clearly differentiated formulation with identifiable, surviving claims.

What formulations are protected by promethazine hydrochloride plain patents, and where do filing strategies focus?

Generic strategies usually focus on:

Demonstrating bioequivalence (for oral solids and liquids where required)
Validating stability and shelf life under the local compendial standards
Ensuring injectable sterility and compatibility
Packaging and labeling compliance for safety messaging

Formulation IP risk is primarily relevant when competing products differ meaningfully in:

Release profile
Solubilizer systems (in oral liquids)
Viscosity or preservative systems
Sterility and container closure systems (injectables)

In a “plain” investment thesis, the actionable point is: file differentiation only matters if it is tied to enforceable claims or to a defensible regulatory pathway that competitor filings cannot easily replicate.

What generic entry risks exist for promethazine hydrochloride plain?

Even without patent barriers, generic entry risk manifests as:

Price compression on tenders
Margin volatility due to sudden supply increases
Failures of competitor manufacturing or quality events that temporarily improve prices for incumbents

If the investor’s plan is to rely on premium pricing, risk is that entrants will quickly undercut unless there is:

A contract in place
A distribution advantage
A superior supply reliability record
A differentiated formulation with demonstrable performance

What does FDA regulatory strategy look like for promethazine HCl plain generics?

For investment underwriting in the US, the relevant issues are:

ANDA pathway selection
Bioequivalence requirements
Labeling compliance including safety considerations consistent with reference labeling
cGMP and facility readiness for approval maintenance
Pharmacovigilance capacity

These factors are operationally material, but they rarely create long-horizon exclusivity for plain molecules.

Which companies are likely competing for promethazine HCl plain supply, and how is market power distributed?

Competition in established antihistamine generics is usually dispersed across:

Large global generic manufacturers
Regional generic makers
Contract manufacturers that supply multiple labelers
Hospital/wholesaler private label programs in some markets

Market power tends to concentrate around:

Companies with stable supply
Low-cost manufacturing footprints
Strong regulatory track records and rapid response to demand spikes

A precise competitive roster and market-share split cannot be listed accurately without a specified dosage form and geography.

What patent litigation affects promethazine hydrochloride plain generics?

Litigation is uncommon for plain antihistamine generics unless:

A specific formulation/process is protected with late-cycle patents
A branded/reference product lists patents still in force
A Paragraph IV strategy is pursued against an ANDA challenger

Without the named reference product and dosage form, litigation impact cannot be correctly enumerated.

How does promethazine HCl plain compare with other antihistamines for investment attractiveness?

Relative attractiveness generally follows:

Newer therapeutics with patent runway: higher upside but higher clinical/regulatory risk
Older, off-patent antihistamines: lower upside, lower scientific risk, high dependence on commercialization and manufacturing excellence

For a promethazine HCl plain thesis, the investment “edge” typically comes from:

Cost leadership
Supply assurance
Efficient regulatory maintenance
Targeting institutional channels with stable demand

Commercial sizing: what revenue exposure is typical for promethazine HCl plain?

Revenue exposure is highly dosage-form and geography dependent:

Hospital procurement can generate stable volume but tight margins
OTC segments can have fluctuating demand
Injectable supply may have episodic demand spikes and procurement discontinuities

A quantified revenue model requires:

Specific product listing
Historical sales in target region
Tender dynamics
Competitor price baselines

Those data are not present in the input, so a complete commercial sizing cannot be produced here.

Key Takeaways

Promethazine hydrochloride plain is a mature, off-patent generic in most major markets, so investment returns usually come from manufacturing, regulatory execution, and distribution, not from surviving molecule-level IP.
The decisive variable is product specificity: dosage form, strength, route, and jurisdiction determine whether any remaining formulation/process exclusivity exists.
Generic entry risk is structurally high due to the breadth of competitors; margin defense depends on contracts, supply reliability, and cost position.
Patent and Orange Book-driven litigation is unlikely at a molecule level, but can still occur for specific reference products or differentiated formulations, which must be checked against the exact product listing.
Investment underwriting should treat promethazine HCl plain as a portfolio, operations, and commercialization bet rather than a patent runway bet.

FAQs

How can a promethazine HCl plain generics manufacturer differentiate without patent protection?
What operational KPIs matter most for institutional tender contracts for promethazine products?
Do injectables of promethazine HCl carry higher regulatory and supply risk than oral solids?
What labeling and safety requirements most affect market access for first-generation antihistamines?
How does competitor pricing behavior typically change after new generic approvals for legacy antihistamines?

References (APA)

US Food and Drug Administration. Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. FDA. https://www.accessdata.fda.gov/scripts/cder/daf/
US Food and Drug Administration. ANDA Drug Development and the Approval Process. FDA. https://www.fda.gov/
FDA. Approved Drug Products: Specified submissions. FDA. https://www.fda.gov/

PROMETHAZINE HYDROCHLORIDE PLAIN Drug Patent Profile

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Summary for PROMETHAZINE HYDROCHLORIDE PLAIN

US Patents and Regulatory Information for PROMETHAZINE HYDROCHLORIDE PLAIN