ERYTHROCIN Drug Patent Profile

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

Erythrocin is a drug marketed by Abbott, Hospira, and Azurity. and is included in five NDAs.

The generic ingredient in ERYTHROCIN is erythromycin stearate. There are two drug master file entries for this compound. Additional details are available on the erythromycin stearate profile page.

Summary for ERYTHROCIN

US Patents:	0
Applicants:	3
NDAs:	5
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	1
Clinical Trials:	1
Drug Prices:	Drug price information for ERYTHROCIN
DailyMed Link:	ERYTHROCIN at DailyMed

See drug prices for ERYTHROCIN

See drug sales revenues for ERYTHROCIN

Recent Clinical Trials for ERYTHROCIN

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

Sponsor	Phase
Janssen Research & Development, LLC	Phase 1

See all ERYTHROCIN clinical trials

Pharmacology for ERYTHROCIN

Drug Class	Macrolide Antimicrobial Macrolide
Physiological Effect	Decreased Sebaceous Gland Activity

US Patents and Regulatory Information for ERYTHROCIN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Abbott	ERYTHROCIN	erythromycin lactobionate	INJECTABLE;INJECTION	062586-002	Jan 4, 1988		DISCN	No	No
Hospira	ERYTHROCIN	erythromycin lactobionate	INJECTABLE;INJECTION	050182-002	Approved Prior to Jan 1, 1982		DISCN	No	No
Hospira	ERYTHROCIN	erythromycin lactobionate	INJECTABLE;INJECTION	050182-003	Approved Prior to Jan 1, 1982		DISCN	No	No

Erythrocin Market Dynamics, Financial Trajectory, Patent Status, and Generic Competition

Last updated: November 10, 2026

Erythrocin is a legacy brand of erythromycin, a macrolide antibiotic. Its commercial value has shifted from branded prescription sales to low-margin generic supply, hospital procurement, and limited niche use. The product has no meaningful remaining U.S. patent exclusivity, no current branded revenue base that is publicly reported as a standalone line item, and substantial substitution pressure from azithromycin, clarithromycin, doxycycline, amoxicillin, and other antibiotics.

What is Erythrocin and who manufactures it?

Erythrocin is associated with erythromycin products in several dosage forms, including oral tablets, oral suspensions, and intravenous erythromycin lactobionate. Erythromycin is approved for selected respiratory, skin, soft-tissue, and sexually transmitted infections, as well as certain prophylactic and pediatric indications.

The historical Erythrocin brand was associated with Abbott Laboratories. Abbott separated its research-based pharmaceutical business into AbbVie in 2013, while its established pharmaceutical products were transferred to different commercial portfolios over time. Current erythromycin products in the United States are primarily marketed by generic manufacturers rather than through a dominant Erythrocin-branded franchise.

Product category	Active ingredient	Typical use	Current commercial position
Erythrocin oral products	Erythromycin base or salt	Bacterial infections	Predominantly generic
Erythrocin lactobionate injection	Erythromycin lactobionate	Hospital and intravenous treatment	Limited institutional market
Erythromycin ethylsuccinate suspension	Erythromycin ethylsuccinate	Pediatric and oral treatment	Generic, price-sensitive
Erythromycin stearate tablets	Erythromycin stearate	Oral antibacterial therapy	Generic and declining
Erythromycin topical products	Erythromycin	Acne and dermatology	Competes with newer topical therapies

The FDA’s labeling database identifies erythromycin products by active ingredient and dosage form, while individual manufacturers hold the relevant abbreviated new drug applications, or ANDAs, for generic versions.[1]

What is the FDA regulatory status of Erythrocin?

Erythromycin is an established active ingredient with long-standing FDA approval. Erythrocin does not have the regulatory profile of a recently approved branded drug. Its market is governed by legacy approvals, generic approvals, manufacturing capacity, and procurement economics.

The FDA has approved erythromycin in multiple salt and ester forms because formulation affects absorption, tolerability, stability, and route of administration. Common forms include:

• Erythromycin base
• Erythromycin ethylsuccinate
• Erythromycin stearate
• Erythromycin lactobionate
• Erythromycin delayed-release and enteric-coated products

The clinical market has contracted because physicians often prefer newer macrolides or non-macrolide antibiotics with more convenient dosing and improved tolerability. Erythromycin remains relevant in selected patients, including some pediatric populations and patients requiring an established macrolide alternative.

What patents protect Erythrocin and when did exclusivity expire?

No meaningful U.S. patent exclusivity remains for the core erythromycin molecule or the historical Erythrocin brand. Erythromycin was discovered and commercialized decades before the modern Orange Book patent framework became commercially relevant for the product.

IP category	Status for Erythrocin
Core erythromycin composition patent	Expired
Historical process patents	Expired or commercially immaterial
Basic oral formulation protection	Expired
Erythromycin salt and ester protection	Expired or bypassed by alternative forms
Method-of-use patents	No material current exclusivity identified
Current Orange Book strategy	Generic competition rather than branded patent enforcement

The FDA Orange Book lists patents and regulatory exclusivity for approved products when applicable. Legacy erythromycin products do not have a current patent barrier comparable with newer branded antibiotics.[2]

How many patents cover Erythrocin?

The commercially relevant answer is zero current patents that block ordinary generic erythromycin competition in the United States. Historical patents may appear in patent databases, including process, formulation, or salt-related filings, but those records do not create current market exclusivity.

A patent search must distinguish between:

1. Expired patents that describe erythromycin chemistry.
2. Abandoned or lapsed applications.
3. Patents covering a specific manufacturing process.
4. Patents listed in the Orange Book for a particular approved product.
5. Patents that remain enforceable but do not block alternative generic processes or formulations.

For Erythrocin, the second through fourth categories do not create a meaningful barrier to standard generic entry.

What is the Orange Book status of Erythrocin?

Erythrocin has no current Orange Book position that supports branded exclusivity comparable with a protected new chemical entity. The relevant FDA records are product-specific and may include discontinued, historical, or generic erythromycin entries.

An Orange Book listing does not itself prove that a product generates material revenue. The commercial question is whether the listed product remains actively marketed, has a recognized brand, and faces approved ANDA substitution. For erythromycin, generic substitution and therapeutic substitution have largely displaced the historical branded franchise.

The FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations identifies therapeutically equivalent generic products where applicable.[2] State substitution rules and hospital purchasing contracts then influence actual use.

What is the financial trajectory of Erythrocin?

Erythrocin’s financial trajectory is a long-term decline from branded-antibiotic economics to commodity-style generic economics.

Historical branded phase

During the earlier commercial life of erythromycin, Erythrocin benefited from:

• Broad physician familiarity.
• Pediatric use.
• Limited competition from newer macrolides.
• Multiple oral and injectable formulations.
• Hospital demand for intravenous erythromycin.

Revenue was historically generated through branded pricing and formulation breadth. The product’s age, however, made it vulnerable to patent expiry and generic substitution.

Generic erosion phase

After generic entry, prices declined and market share fragmented among manufacturers. The erosion was reinforced by:

• Low barriers to therapeutic substitution.
• Multiple approved erythromycin formulations.
• Use of preferred formulary alternatives.
• Declining physician preference for erythromycin.
• Antibiotic stewardship programs.
• Supply interruptions affecting low-volume sterile products.
• Manufacturing competition from contract and generic suppliers.

Current phase

There is no widely reported standalone Erythrocin revenue stream in the public financial filings of major pharmaceutical companies. Erythromycin revenue is generally aggregated into broader established products, hospital products, or generic portfolios. This makes a precise current Erythrocin valuation unavailable from public company reporting.

The economic profile is likely characterized by low unit prices, limited promotional spending, and revenue concentration in specific dosage forms or institutional contracts. Injectable erythromycin can have greater revenue per unit than older oral tablets, but its market is smaller and more exposed to manufacturing, quality, and supply-chain risk.

What market forces affect Erythrocin demand?

Erythrocin demand is determined less by brand marketing than by clinical guidelines, local resistance patterns, formulary policy, and availability.

Therapeutic substitution

Azithromycin and clarithromycin generally offer more convenient dosing than erythromycin. Doxycycline, amoxicillin, amoxicillin-clavulanate, cephalosporins, and other antibiotics compete across overlapping indications.

Erythromycin may retain use where:

• A macrolide is clinically preferred.
• Pediatric formulation availability is important.
• A physician has a specific tolerance or allergy rationale.
• Hospital protocols require an established intravenous macrolide.
• Local formulary economics favor a low-cost generic.

Resistance and tolerability

Erythromycin resistance reduces demand in infections where macrolide susceptibility is uncertain. Gastrointestinal adverse effects also limit use. Erythromycin has clinically relevant drug-interaction and cardiac-risk considerations, including CYP3A4-mediated interactions and QT prolongation concerns described in FDA labeling.[3]

Stewardship

Antibiotic stewardship programs reduce unnecessary prescribing and favor narrow, guideline-supported use. This constrains volume but can preserve demand for cases where erythromycin remains clinically appropriate.

How does Erythrocin compare with azithromycin and clarithromycin?

Attribute	Erythrocin	Azithromycin	Clarithromycin
Drug class	Macrolide	Macrolide azalide	Macrolide
Dosing convenience	Generally less convenient	Usually more convenient	More convenient
Gastrointestinal tolerability	Relatively weaker	Generally improved	Intermediate
Brand patent position	Expired	Expired in major markets	Expired in major markets
Generic competition	Extensive	Extensive	Extensive
Hospital injectable relevance	Selective	Available, depending on product	Available, depending on product
Commercial growth outlook	Declining or stable niche	Mature generic market	Mature generic market
Main commercial advantage	Low cost and clinical familiarity	Dosing convenience	Broader modern macrolide use

Erythrocin lacks a clear commercial advantage over newer macrolides except in selected clinical and procurement settings. Its strongest residual position is as an established, low-cost option rather than as a differentiated branded product.

What generic entry risks exist for Erythrocin?

Generic entry risk is effectively realized rather than prospective. Erythromycin has long faced generic competition, and the principal risks now are margin compression, supplier exits, and therapeutic substitution.

Generic risks

• Additional ANDA approvals can reduce prices.
• Wholesalers can consolidate purchases among fewer suppliers.
• Hospitals can substitute other macrolides.
• Low volumes can make manufacturers vulnerable to production interruptions.
• Sterile injectable manufacturing can create quality-control and capacity risks.
• Buyers can shift to alternative antibiotics when supply becomes unreliable.

For a company holding a remaining Erythrocin-branded product, the key risk is not a future Paragraph IV challenge. It is the continuing loss of branded demand to approved generics and clinically preferred alternatives.

Are there Paragraph IV challenges or patent litigation involving Erythrocin?

A current Paragraph IV litigation threat is not commercially material for the historical Erythrocin franchise. Paragraph IV litigation applies when an ANDA applicant certifies that a listed patent is invalid, unenforceable, or will not be infringed. With the core erythromycin patent estate expired, generic applicants do not need to wait for a modern branded patent cliff.

No major current U.S. patent litigation campaign is associated with the historical Erythrocin brand in the public commercial record. Litigation risk would be more likely to arise from:

• A newly developed erythromycin formulation.
• A proprietary delivery system.
• A combination product.
• A manufacturing process with enforceable claims.
• A different branded product using erythromycin as an ingredient.

Those scenarios would involve the new formulation or process, not the conventional Erythrocin product.

What manufacturing and intellectual-property barriers remain?

The active pharmaceutical ingredient is mature, and conventional erythromycin chemistry does not create a strong exclusivity barrier. Manufacturing barriers are operational rather than patent-based.

Relevant barriers include:

• Fermentation and purification know-how.
• Control of impurities and degradation products.
• Salt or ester conversion.
• Stability in liquid suspensions.
• Taste masking for pediatric products.
• Sterile manufacturing for intravenous products.
• Validated analytical methods.
• Regulatory compliance at API and finished-dose sites.

These barriers can reduce the number of active suppliers without creating sustainable branded pricing power. A supplier with reliable sterile capacity may obtain better contracting terms, but the advantage is usually temporary and procurement-driven.

What licensing deals affect Erythrocin?

No major current licensing transaction is publicly associated with Erythrocin as a standalone commercial asset. Historical rights may have moved through corporate transactions, product divestitures, or portfolio reorganizations, but these arrangements do not appear to support a separately disclosed growth franchise.

The absence of a visible licensing market is consistent with the product’s status as an established generic antibiotic. Potential transactions would more likely involve:

• A bundle of hospital injectables.
• A generic portfolio acquisition.
• A contract manufacturing agreement.
• Regional distribution rights.
• A formulation improvement using erythromycin.

What is the outlook for Erythrocin revenue?

The base-case outlook is continued low-value maturity rather than a return to branded growth.

Driver	Expected effect
Core patent expiry	Permanent generic pricing pressure
Newer macrolides	Lower erythromycin volume
Antibiotic stewardship	Lower inappropriate use
Pediatric and selected clinical demand	Supports a residual niche
Injectable supply constraints	Can create temporary price increases
Generic supplier consolidation	May improve surviving suppliers’ volumes
No differentiated formulation	Limits margin expansion
No current branded promotion	Limits demand recovery

A temporary increase in revenue could occur if competing injectable antibiotics experience shortages or if a supplier secures a hospital contract. That would represent supply-driven pricing or volume, not a durable patent-protected recovery.

Key Takeaways

• Erythrocin is a legacy erythromycin brand with no meaningful current U.S. patent exclusivity.
• The product’s commercial value has moved from branded sales to generic and institutional supply.
• Public companies do not generally disclose standalone Erythrocin revenue.
• The main competitive threats are azithromycin, clarithromycin, doxycycline, beta-lactam antibiotics, and hospital formulary substitution.
• Paragraph IV litigation is not a material current risk because the core erythromycin patent estate is expired.
• Remaining barriers are manufacturing, quality, sterile capacity, supply reliability, and regulatory compliance.
• The financial outlook is mature and low-margin, with limited potential for durable growth absent a new formulation or supply disruption.
• Any valuation should focus on dosage form, active marketing status, supplier concentration, hospital contracts, and geographic demand rather than the historical brand name alone.

FAQs

Is Erythrocin still sold in the United States?

Erythromycin remains available in selected oral and injectable formulations, but availability depends on the specific dosage form, manufacturer, and current distribution status. The historical Erythrocin brand has largely been replaced by generic erythromycin products.

Is Erythrocin the same as erythromycin?

Yes. Erythrocin is a brand associated with erythromycin products. The active ingredient may be supplied as erythromycin base, ethylsuccinate, stearate, or lactobionate depending on the dosage form.

Can a generic company launch Erythrocin without a patent challenge?

A generic company can market an approved erythromycin product after satisfying FDA requirements because the core product patents are expired. The company would need approval for its specific formulation, manufacturing process, labeling, and dosage form.

Does Erythrocin have biosimilar competition?

No. Erythromycin is a small-molecule antibiotic, not a biologic. Competition occurs through generic drug applications rather than the FDA biosimilar pathway.

Could a new erythromycin formulation obtain patent protection?

Yes. A novel delivery system, stable formulation, combination product, or manufacturing process could receive patents if it meets statutory novelty and non-obviousness requirements. Such protection would apply to the new innovation, not to conventional erythromycin or the historical Erythrocin brand.

References

1. U.S. Food and Drug Administration. (n.d.). Drugs@FDA: FDA-approved drugs. https://www.accessdata.fda.gov/scripts/cder/daf/

2. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book

3. U.S. Food and Drug Administration. (n.d.). Erythromycin prescribing information. DailyMed. https://dailymed.nlm.nih.gov/dailymed/

4. U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application process for generic drugs. https://www.fda.gov/drugs/abbreviated-new-drug-application-anda/anda-process

5. U.S. Food and Drug Administration. (n.d.). Antimicrobial resistance and antibiotic stewardship. https://www.fda.gov/animal-veterinary/safety-health/antimicrobial-resistance-information

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