HYDROFLUMETHIAZIDE AND RESERPINE Drug Patent Profile

Which patents cover Hydroflumethiazide And Reserpine, and when can generic versions of Hydroflumethiazide And Reserpine launch?

Hydroflumethiazide And Reserpine is a drug marketed by Usl Pharma and Watson Labs and is included in three NDAs.

The generic ingredient in HYDROFLUMETHIAZIDE AND RESERPINE is hydroflumethiazide; reserpine. There are two drug master file entries for this compound. Additional details are available on the hydroflumethiazide; reserpine profile page.

Summary for HYDROFLUMETHIAZIDE AND RESERPINE

US Patents:	0
Applicants:	2
NDAs:	3

US Patents and Regulatory Information for HYDROFLUMETHIAZIDE AND RESERPINE

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Usl Pharma	HYDROFLUMETHIAZIDE AND RESERPINE	hydroflumethiazide; reserpine	TABLET;ORAL	088195-001	Oct 26, 1983		DISCN	No	No
Watson Labs	HYDROFLUMETHIAZIDE AND RESERPINE	hydroflumethiazide; reserpine	TABLET;ORAL	088127-001	Mar 22, 1983		DISCN	No	No
Watson Labs	HYDROFLUMETHIAZIDE AND RESERPINE	hydroflumethiazide; reserpine	TABLET;ORAL	088110-001	Mar 22, 1983		DISCN	No	No

Last updated: July 15, 2026

Hydroflumethiazide and Reserpine Drug Investment Scenario: Patent, Exclusivity, Competitive Risk, and Revenue Fundamentals

Executive summary: Hydroflumethiazide plus reserpine is a fixed-dose combination (FDC) with a mature, off-patent commercial footprint in the US and multiple markets. Investment upside is primarily tied to (1) whether any branded product still has enforceable US patent or regulatory exclusivity, (2) whether generics are meaningfully supply-constrained, and (3) whether the portfolio owner can sustain branded pricing through limited competitors or higher regulatory barriers. Absent clear, currently enforceable US exclusivity/patent coverage for an active, commercially scaled product, the risk profile shifts toward commoditization: price erosion, low incremental R&D value, and limited defensibility outside reformulation or novel delivery/indication expansions.

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What patents protect hydroflumethiazide and reserpine fixed-dose combinations in the US?

Featured snippet answer: For most marketed hydroflumethiazide plus reserpine FDCs, the core actives are old and generally not covered by active US composition-of-matter patents. Protection, when it exists, usually resides in secondary patent categories: formulation, specific tablet strengths, manufacturing processes, or method-of-use tied to a particular dosing regimen.

Patent estate structure investors should test

1. Composition of matter (rare for older FDCs)
   • Hydroflumethiazide and reserpine are long-established actives, so broad “new chemical entity” coverage is unlikely to be active unless a later-generation salt/co-crystal, polymorph, or new formulation was patented.
2. Formulation and formulation-process patents (most plausible)
   • Controlled-release or taste-masked tablets, specific excipient matrices, or stability-driven manufacturing steps.
3. Method-of-use patents (common pattern if any remain)
   • Tied to an approved regimen, for example, a defined dosing schedule or a narrower hypertension subgroup.

Why this matters for investment

• If the FDC has no active US Orange Book drug-product patents covering the currently marketed strengths, the business case shifts to a market share and supply play, not an IP moat play.
• If there are listed formulation/process patents, investors need to assess whether those patents cover the specific ANDA-relevant drug product (same strength, same release characteristics, same listed conditions).

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When does hydroflumethiazide and reserpine lose exclusivity and patent protection?

Featured snippet answer: For older antihypertensive FDCs built from legacy molecules, exclusivity typically runs out years earlier than many modern cardiovascular portfolios. Practically, the relevant endpoint for generic entry is whether any FDA-listed patents remain unexpired for the specific marketed strength and dosage form.

How to time generic entry risk

• Use a three-layer exclusivity lens:
  1. Regulatory exclusivity (Hatch-Waxman exclusivity type, if any)
  2. Orange Book listed drug product patents (method/use, formulation, and device-related patents)
  3. Litigation-driven delays (settlements or injunctions)

Investment implication

• If the company’s product is already on the far side of patent expiration, the main levers are:
  • maintaining supply,
  • avoiding price collapse through differentiation (NDC, dosage form, labeling),
  • and reducing generic competitive penetration.

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Which companies are likely to challenge hydroflumethiazide and reserpine products with Paragraph IV ANDAs?

Featured snippet answer: Paragraph IV challenges are usually filed by established generic and biosimilar-adjacent generic manufacturers that maintain broad hypertension portfolios. However, the actual list depends on which specific product is currently on the market and which NDA/ANDA is tied to the brand’s FDA listing.

What to look for in generic challenger signals

• ANDA filings referencing the same active FDC and strength.
• Recent 30-month stay triggers.
• Public settlements that indicate which challenger obtained market access first.

Investment implication

• If multiple ANDAs are active and no long litigation runway exists, the expected outcome is rapid erosion to low-margin “commodity” pricing.

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What is the Orange Book status of hydroflumethiazide and reserpine?

Featured snippet answer: Orange Book status is decisive for exclusivity and generic entry timing. For legacy FDCs, many NDCs show either:

• no unexpired listed patents, or
• only expired or narrowly scoped patents (formulation-specific, not preventing generic equivalents).

How investors should interpret Orange Book listings for this FDC

• Determine:
  • whether the active product is still branded and still has listed patents,
  • whether the listed patents are drug substance or drug product,
  • whether patents are categorized as method-of-use (section IV) or formulation/process (section II),
  • and whether those listed patents map to the strength and dosage form that drive sales.

Business consequence

• Orange Book with multiple unexpired drug product patents can support a longer pricing runway.
• Orange Book with no active listed patents usually signals “generic will win,” making branded economics less defensible unless a distribution or supply advantage exists.

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How strong is the patent estate for hydroflumethiazide plus reserpine tablet strengths?

Featured snippet answer: Patent strength for these older actives is usually modest. The realistic assessment is whether any listed patents still cover:

• the exact tablet strength(s),
• the exact release/dissolution profile,
• and manufacturing steps that a generic would need to replicate or avoid.

Patent strength scoring investors can apply

• Breadth: Does protection cover all strengths or only specific ones?
• Narrowness: Is the patent a specific excipient matrix or process?
• Enforceability risk: Any expiration, disclaimer, or lack of exclusivity alignment.
• Generic “design-around” feasibility: Can an ANDA use different excipients or process without infringing?

Outcome for investment

• Weak estates generally compress margin potential and reduce expected return unless the company has:
  • exclusive distribution,
  • supply-side leverage,
  • or a rare regulatory bottleneck.

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What formulations are protected by hydroflumethiazide and reserpine patents?

Featured snippet answer: When formulation patents exist for legacy FDCs, they are usually tied to tablet composition and manufacturing controls rather than new active molecules.

Formulation categories to test for

• Stability and moisture control measures
• Disintegration or dissolution specification methods
• Excipient selection and tablet hardness/coat parameters
• Process validation patents (granulation, compression, coating, sterilization, if relevant)
• Fixed-dose compatibility between hydroflumethiazide and reserpine (if patented)

Investment implication

• Formulation/process patents can delay some ANDAs but seldom stop all generic entry unless the patent claims are broad and the generic process must match in detail.

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How does hydroflumethiazide plus reserpine compare with alternative antihypertensive fixed-dose regimens on IP and market risk?

Featured snippet answer: Many fixed-dose antihypertensive combinations are newer and more IP-protected than legacy reserpine-containing products. Hydroflumethiazide plus reserpine typically faces greater long-run commoditization risk compared with newer branded classes (ACE inhibitors, ARBs, ARNI, SGLT2 inhibitors, and modern thiazide combinations), unless a specific branded product still retains unexpired listed patents.

Competitive risk vector

• Clinicians and payers often prefer modern regimens with better tolerability profiles.
• That preference can shrink brand durability even before patent expiry.

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What generic entry risks exist for hydroflumethiazide and reserpine tablets?

Featured snippet answer: The generic entry risk is typically high because older FDC actives generally have limited remaining IP. The key variable is not whether generics can file, but how quickly they can achieve:

• approved ANDA status,
• launch readiness,
• and competitive pricing.

Launch accelerants

• Multiple ANDA approvals
• Settlements allowing “at-risk” or early launch
• Supply constraints if the brand depends on a single manufacturing site

Investment implication

• If demand is stable but supply is contestable, entrants can quickly drive price to low levels, hurting ROI.

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What patent litigation affects hydroflumethiazide and reserpine products?

Featured snippet answer: For older FDCs, litigation usually occurs around ANDA certifications and can resolve into settlements that set launch dates. The investment relevance is whether any current litigation blocks generic competition for a specific strength/NDC.

How to use litigation as a forecast tool

• Look for:
  • active case status (not historical)
  • any court-ordered injunctions
  • settlement “trigger” language indicating market start dates

Investment implication

• If there is no current litigation around the marketed NDC, the expected horizon is near-term price pressure.

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What licensing deals and settlements are typical for legacy antihypertensive FDCs?

Featured snippet answer: When settlements exist, they usually involve:

• non-infringement or validity concessions in exchange for delayed launch,
• or a timeline where generic entry occurs at a specified date.

Investment implication

• Settlements can create a short-term exclusivity window even without strong intrinsic patent strength.
• The longer the settlement horizon without additional patent listings, the more investors should assume competitors will still erode margins afterward.

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What is the FDA regulatory pathway status for hydroflumethiazide and reserpine?

Featured snippet answer: The combination is typically marketed through established NDA/ANDA pathways, with generics using ANDA references to the branded listed drug for specific strengths.

Investors should focus on

• Whether the product remains an NDA-listed branded drug with currently marketed NDCs.
• Whether recent product switches or label changes suggest ongoing lifecycle management.

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What are the commercial fundamentals for hydroflumethiazide and reserpine: revenue drivers, demand durability, and margin pressure?

Featured snippet answer: Commercial fundamentals are driven by stable but price-sensitive demand in hypertension and by payer coverage. For legacy antihypertensive FDCs, the margin profile is usually under pressure due to:

• generic substitution,
• tender-based pricing,
• and limited differentiation.

Core fundamentals checklist

• Unit demand stability: Hypertension treatment is chronic, but regimen selection varies with side-effect profiles.
• Pricing trend: Typically downward toward generic parity.
• Gross-to-net: Higher for branded products; lower once generic.
• Channel exposure: Wholesaler and PBM contracting influence net revenue.
• Supply reliability: Manufacturing disruption can temporarily lift pricing but also risks inventory loss.

Investment scenario

• Best-case: Limited number of competitors, some NDC-level differentiation, and a still-active Orange Book patent stack that delays full commoditization.
• Base-case: Several competitors present, brand share erodes gradually, and returns depend on scale, contracting, and cost reduction.
• Downside: Multiple ANDAs launch with rapid volume shift and net price collapse.

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How does biosimilar risk apply to hydroflumethiazide and reserpine?

Featured snippet answer: Biosimilar risk is not applicable because this is a small-molecule combination, not a biologic.

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Geographic coverage: where is hydroflumethiazide and reserpine most exposed to generic substitution?

Featured snippet answer: The highest risk is in markets with active generics procurement and mature regulatory approvals, particularly the US and EU where fixed-dose combination generics are common.

Investment implication

• Cross-market generic penetration can force blended pricing down even if one geography retains share.

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Manufacturing and IP barriers: what could delay generic competition?

Featured snippet answer: For legacy tablets, barriers typically come from manufacturing execution and regulatory chemistry, not from deep IP.

Key barriers

• Reliable sourcing of both actives to meet stability specs
• Tablet formulation robustness to prevent potency loss
• Process validation and batch consistency
• Regulatory inspection history affecting approval timelines

Investment implication

• A brand with strong quality systems can retain supply share even when patents are weak.

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Key Takeaways

• Hydroflumethiazide plus reserpine is an aging fixed-dose antihypertensive combination where IP-driven exclusivity is usually limited; investment upside depends on whether current, strength-specific Orange Book listings still create defensible barriers.
• If Orange Book shows no unexpired drug-product patents for the active NDC strengths, the likely trajectory is rapid generic-driven price compression and low margin durability.
• Litigation and Paragraph IV activity are decisive only when ongoing for the currently marketed product and strength; otherwise, expect commoditization.
• Commercial fundamentals skew toward supply, contracting, and manufacturing reliability rather than R&D differentiation.

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FAQs

1. What economic impact do 30-month ANDA stays have for legacy fixed-dose antihypertensives?
2. How do PBM and wholesaler contracting dynamics affect net pricing for hypertension FDC generics?
3. Which Orange Book patent categories most often matter for generic substitution of older tablets?
4. What manufacturing quality issues most commonly delay ANDA approval for oral solid dosage combinations?
5. How should investors model demand risk when prescriber preference shifts away from reserpine-containing regimens?

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References

No sources were provided or can be cited from the prompt.