EDROPHONIUM CHLORIDE - Generic Drug Details

What are the generic sources for edrophonium chloride and what is the scope of patent protection?

Edrophonium chloride is the generic ingredient in six branded drugs marketed by Hospira, Watson Labs, Pharmobedient, Organon Usa Inc, and Pai Holdings Pharm, and is included in six NDAs. Additional information is available in the individual branded drug profile pages.

Summary for EDROPHONIUM CHLORIDE

US Patents:	0
Tradenames:	6
Applicants:	5
NDAs:	6
Drug Master File Entries:	3
Raw Ingredient (Bulk) Api Vendors:	68
Patent Applications:	6,044
DailyMed Link:	EDROPHONIUM CHLORIDE at DailyMed

Medical Subject Heading (MeSH) Categories for EDROPHONIUM CHLORIDE

Antidotes

Cholinesterase Inhibitors

Anatomical Therapeutic Chemical (ATC) Classes for EDROPHONIUM CHLORIDE

V04CX	Other diagnostic agents
V04C	OTHER DIAGNOSTIC AGENTS
V04	DIAGNOSTIC AGENTS
V	Various

US Patents and Regulatory Information for EDROPHONIUM CHLORIDE

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Watson Labs	EDROPHONIUM CHLORIDE	edrophonium chloride	INJECTABLE;INJECTION	040044-001	Mar 20, 1996		DISCN	No	No
Pharmobedient	ENLON	edrophonium chloride	INJECTABLE;INJECTION	088873-001	Aug 6, 1985		DISCN	No	No
Watson Labs	EDROPHONIUM CHLORIDE PRESERVATIVE FREE	edrophonium chloride	INJECTABLE;INJECTION	040043-001	Mar 20, 1996		DISCN	No	No
Pai Holdings Pharm	TENSILON	edrophonium chloride	INJECTABLE;INJECTION	007959-001	Approved Prior to Jan 1, 1982		DISCN	Yes	No
Organon Usa Inc	REVERSOL	edrophonium chloride	INJECTABLE;INJECTION	089624-001	May 13, 1988		DISCN	No	No
Hospira	EDROPHONIUM CHLORIDE	edrophonium chloride	INJECTABLE;INJECTION	040131-001	Feb 24, 1998		DISCN	No	No
Pai Holdings Pharm	TENSILON PRESERVATIVE FREE	edrophonium chloride	INJECTABLE;INJECTION	007959-002	Approved Prior to Jan 1, 1982		DISCN	Yes	No

Edrophonium Chloride Market Dynamics, Patent Status, FDA History, and Financial Trajectory

Last updated: September 9, 2026

Edrophonium chloride is a legacy acetylcholinesterase inhibitor with no material branded market in the United States. Its historical uses included diagnosis of myasthenia gravis, short-term reversal of nondepolarizing neuromuscular blockade, and assessment of cholinergic or myasthenic syndromes. The product has lost commercial relevance because safer and more practical alternatives replaced most uses, while the underlying compound has long been outside meaningful patent exclusivity.

The current market is characterized by discontinued or limited commercial supply, low demand, hospital formulary substitution, and negligible publicly disclosed product revenue. The main commercial risks are supply continuity, regulatory maintenance, and clinical obsolescence rather than patent litigation or generic competition.

What is edrophonium chloride and how is it used?

Edrophonium chloride is a short-acting, reversible acetylcholinesterase inhibitor. It increases acetylcholine concentrations at neuromuscular junctions and produces a rapid but brief pharmacologic effect.

Historically, clinicians used edrophonium chloride for:

• Temporary improvement of muscle weakness in myasthenia gravis.
• Differentiation between myasthenic and cholinergic weakness.
• Reversal of nondepolarizing neuromuscular blockade after surgery.
• Diagnostic testing before the adoption of more modern electrophysiologic and therapeutic approaches.

The drug was administered intravenously or intramuscularly. Its short duration made it useful for diagnostic testing, but the same characteristic limited its role in chronic treatment.

Neostigmine and pyridostigmine replaced edrophonium for many therapeutic applications. Modern neuromuscular monitoring and reversal agents, including sugammadex, reduced the role of acetylcholinesterase inhibitors in perioperative practice. The FDA approved sugammadex for reversal of certain neuromuscular blockades in 2015, expanding the alternatives available to anesthesiologists (FDA, 2015).

What is the FDA regulatory status of edrophonium chloride?

Edrophonium chloride has historical FDA approval as an injectable prescription drug, but commercial status in the United States has deteriorated substantially.

The FDA has listed edrophonium chloride injection products as discontinued. A discontinued designation does not necessarily mean that FDA withdrew approval for safety or efficacy reasons. FDA guidance distinguishes products that are no longer marketed from products withdrawn for safety or effectiveness concerns (FDA, n.d.-a).

DailyMed has carried labeling for edrophonium chloride injection products, including products supplied by generic manufacturers and hospital injectable suppliers. Product availability has varied by manufacturer, dosage strength, and hospital purchasing channel (National Library of Medicine, n.d.).

Regulatory issue	Current commercial implication
Historical FDA approval	Established the legal basis for injectable marketing
Discontinued product listings	Indicates loss of regular commercial availability for listed products
Safety withdrawal status	Discontinuation alone does not establish a safety withdrawal
Prescription status	Hospital and clinical-use product, not an over-the-counter medicine
Current demand	Restricted to narrow diagnostic, anesthetic, or specialist uses
Regulatory burden	Injectable manufacturing, sterility, shortage management, and labeling compliance

The product’s regulatory position is therefore best described as legacy-approved but commercially constrained. It should not be treated as a growing FDA pharmaceutical franchise.

When did edrophonium chloride lose market exclusivity?

Edrophonium chloride lost meaningful exclusivity decades ago. The compound was discovered and commercialized in the mid-20th century, and any composition-of-matter protection would have expired long before the modern pharmaceutical patent system became the central commercial barrier for injectable products.

The practical exclusivity timeline is:

Period	Market event
1950s	Edrophonium became established as a short-acting cholinesterase inhibitor
1950s to 1970s	Branded products, including Tensilon, were used in neurology and anesthesia
1970s onward	Generic and hospital-supply versions became commercially possible
1980s to 2000s	Newer therapies reduced diagnostic and therapeutic dependence
2010s	Product discontinuations and supply contraction became more visible
Current period	No meaningful branded exclusivity or durable patent moat

No active composition-of-matter patent should be expected to protect edrophonium chloride in the United States, Europe, or other major pharmaceutical markets. Any remaining patent question would concern a specific formulation, manufacturing process, combination product, or delivery system rather than the active ingredient itself.

What patents protect edrophonium chloride?

The commercial patent estate for edrophonium chloride is effectively exhausted.

Composition-of-matter patents

Edrophonium chloride is an old active pharmaceutical ingredient. Any original compound patent is expired. The market cannot rely on a current composition patent to block generic or compounded supply.

Formulation patents

The injectable dosage form is technically straightforward compared with modern extended-release, depot, biologic, or device-enabled products. Potential claim categories could include:

• Stabilized aqueous solutions.
• Specific preservative systems.
• Unit-dose ampoules or prefilled syringes.
• Concentration and pH ranges.
• Compatibility with infusion or anesthesia systems.
• Combination products containing atropine or another anticholinergic.

These categories would require a currently enforceable patent with applicable claims. No widely recognized active U.S. formulation patent currently defines the commercial edrophonium chloride market.

Method-of-use patents

Historical diagnostic and reversal uses are generally vulnerable to prior art and longstanding clinical practice. A new method-of-use patent would need a narrow, novel indication or dosing protocol. Such a patent would not recreate broad exclusivity for the legacy product.

Manufacturing and process protection

Manufacturing know-how may still affect supply, but trade secrets and process expertise do not create the same exclusionary position as an issued, unexpired patent. The more important barrier is compliance with sterile injectable manufacturing requirements.

What is the Orange Book status of edrophonium chloride?

Edrophonium chloride does not have a commercially significant current Orange Book position comparable to active branded drugs with listed patents and ongoing Paragraph IV litigation.

The Orange Book records FDA-approved drug products and, where applicable, patent and regulatory exclusivity information. For a legacy injectable product that is no longer actively marketed, the relevant commercial conclusion is that there is no meaningful Orange Book patent barrier protecting a current branded franchise (FDA, n.d.-b).

Orange Book question	Assessment
Active branded reference franchise	No material current franchise identified
Listed blocking patents	No meaningful active patent estate expected
Paragraph IV exposure	Low because there is little active branded revenue to defend
Generic approval pathway	Historically available under abbreviated pathways where a reference product and regulatory conditions permit
Commercial dispute risk	Low relative to supply and manufacturing risk

The absence of an active patent moat does not guarantee immediate generic availability. FDA approval, manufacturing capacity, drug shortage conditions, and commercial demand remain separate constraints.

How many patents cover edrophonium chloride?

No material number of active U.S. patents is known to cover the core edrophonium chloride product. The relevant patent count is effectively zero for broad active-ingredient exclusivity.

A patent search could identify expired historical patents, patents assigned to former manufacturers, or unrelated process and formulation claims. Those records would have limited commercial value unless they remain unexpired, cover the marketed product, and have enforceable claims in the relevant jurisdiction.

The patent estate is therefore weak on the dimensions that matter most to investors:

Patent-strength factor	Assessment
Active ingredient protection	Expired
Broad therapeutic-use protection	Expired or vulnerable to prior art
Injectable formulation protection	No established blocking estate
Device protection	Not central to the product
Manufacturing patents	Possible in theory, but not a recognized market barrier
Patent litigation leverage	Low
Life-cycle management potential	Low without a substantially differentiated product

What is the financial trajectory of edrophonium chloride?

Public filings do not provide a reliable standalone revenue series for edrophonium chloride. Historical branded sales were generally reported within broader portfolios, and current generic injectable sales are not normally disclosed by product.

The financial trajectory is nevertheless clear:

1. Revenue expanded during the period when edrophonium was a standard diagnostic and reversal tool.
2. Revenue declined as pyridostigmine, neostigmine, electrophysiologic testing, and newer reversal strategies displaced it.
3. The market fragmented among hospital suppliers and generic manufacturers.
4. Product discontinuations reduced routine purchasing.
5. Current annual product revenue is likely immaterial at the level of major pharmaceutical companies.

The economics of the product are unfavorable:

• Low unit value.
• Limited clinical demand.
• Small procurement volumes.
• Sterile injectable manufacturing costs.
• Regulatory and quality obligations that remain substantial despite low sales.
• Inventory and shortage-management costs.
• Competition from alternative therapies and diagnostic methods.

For a manufacturer, the product may have value as a niche hospital item or portfolio-completion product. It is unlikely to support a standalone commercial organization or meaningful research-and-development program.

Which companies have marketed or supplied edrophonium chloride?

Historical supply has included Roche under the Tensilon brand and later generic injectable manufacturers. U.S. hospital supply has also involved companies such as Hospira, Pfizer, and other injectable-drug suppliers, depending on the period and presentation.

Supplier identity has changed over time because the market is sensitive to manufacturing economics and portfolio rationalization. A company’s historical listing on a label or procurement database does not establish current availability.

Supplier category	Market role
Roche	Historical branded Tensilon supplier
Generic injectable manufacturers	Later supply of edrophonium chloride injection
Hospital wholesalers	Distribution and inventory management
Compounding pharmacies	Potential fallback source where legally and clinically appropriate
International suppliers	Country-specific supply where products remain registered

The market has no dominant current innovator comparable to a company defending a high-value branded drug.

Are there Paragraph IV challenges or edrophonium chloride patent lawsuits?

No major recent Paragraph IV campaign or high-value patent litigation is associated with edrophonium chloride.

Paragraph IV litigation is generally triggered when a generic applicant challenges listed patents protecting a marketed reference drug. Edrophonium chloride lacks the commercial conditions that typically generate such disputes:

• No active high-revenue brand requiring protection.
• No meaningful unexpired composition patent.
• No prominent listed formulation patent.
• Limited economic incentive to litigate over market entry.
• Small addressable demand.

Any historical litigation would be more likely to involve product liability, supply, labeling, or commercial distribution than modern Hatch-Waxman patent litigation.

What generic entry risks exist for edrophonium chloride?

Generic entry risk is high in legal terms but modest in commercial effect.

A manufacturer with an approved injectable product could theoretically enter without confronting a strong patent estate. The practical barriers are different:

• Demonstrating pharmaceutical equivalence.
• Meeting sterile manufacturing requirements.
• Maintaining reliable active pharmaceutical ingredient supply.
• Supporting stability data and container-closure compatibility.
• Managing low-volume economics.
• Securing hospital contracts and wholesaler distribution.

Generic entry would not necessarily produce a large revenue transfer because the remaining market is small. In many cases, the commercial outcome would be additional supply redundancy rather than a major price collapse.

How does edrophonium chloride compare with neostigmine and sugammadex?

Edrophonium is disadvantaged against both drugs in current clinical practice.

Product	Primary role	Commercial position	Competitive advantage
Edrophonium chloride	Short-acting diagnostic or reversal agent	Legacy, limited supply	Rapid onset and short duration
Neostigmine	Reversal of nondepolarizing blockade; cholinergic therapy	Established generic market	Lower cost and broad familiarity
Pyridostigmine	Long-term myasthenia gravis therapy	Established chronic-use market	Longer duration and oral administration
Sugammadex	Reversal of rocuronium and vecuronium blockade	Branded and genericizing market	Faster, selective reversal mechanism

Sugammadex has a stronger contemporary perioperative value proposition, while pyridostigmine remains more relevant for chronic myasthenia gravis treatment. Edrophonium retains niche utility where its short action is clinically advantageous, but its addressable market is narrow.

What manufacturing and geographic barriers affect the market?

The central barrier is sterile injectable production, not intellectual property.

Manufacturing barriers

Manufacturers must manage:

• Sterility assurance.
• Endotoxin controls.
• Aseptic filling.
• Container-closure integrity.
• Shortages of injectable manufacturing capacity.
• Validation of low-volume production lines.
• Pharmacovigilance and labeling maintenance.

These requirements can make a low-demand product uneconomic even when the active ingredient is inexpensive.

Geographic coverage

Availability differs sharply by jurisdiction. A product may be discontinued in the United States while remaining registered or supplied in selected international markets. Regulatory approval, procurement systems, local clinical practice, and national shortage policies determine access.

The European Union, Japan, Canada, Australia, and emerging markets may have different product histories and supply channels. A global commercial assessment therefore requires country-level registration and procurement data rather than extrapolation from U.S. status.

What licensing deals affect edrophonium chloride?

No major current licensing transaction is associated with edrophonium chloride. The product is too old and commercially limited to attract conventional royalty-bearing licensing activity.

Potential transactions would more likely involve:

• Acquisition of an injectable product portfolio.
• Transfer of an abbreviated application or marketing authorization.
• Contract manufacturing.
• Hospital-supply distribution.
• Regional commercialization rights.

These arrangements would be operational rather than strategic platform deals. No significant publicly disclosed licensing revenue stream should be attributed to edrophonium chloride.

What is the outlook for edrophonium chloride?

The base-case outlook is continued contraction with intermittent niche demand. The product could retain a role in specialist neurology, anesthesiology, or shortage-driven hospital purchasing, but it has little potential for material market expansion.

The most relevant commercial scenarios are:

Scenario	Likely result
Continued discontinuations	Greater shortage risk and substitution
New generic entrant	Improved supply, limited revenue growth
Hospital shortage	Temporary price or procurement activity increase
New formulation	Possible niche value, but weak return on investment
Repositioning in a new indication	Low probability without clinical development
Patent-based defense	Not commercially viable because the core estate is expired

Key Takeaways

• Edrophonium chloride is a legacy injectable acetylcholinesterase inhibitor with limited current use.
• The active ingredient has no meaningful remaining composition-of-matter exclusivity.
• No material Orange Book patent estate or current Paragraph IV litigation position defines the market.
• FDA commercial status is constrained by product discontinuations and limited availability.
• Revenue has declined through therapeutic substitution and reduced clinical demand.
• The principal barriers are sterile manufacturing, low-volume economics, and supply continuity.
• Neostigmine, pyridostigmine, modern diagnostics, and sugammadex have reduced the addressable market.
• No major current licensing deal or standalone financial franchise is associated with the product.
• Generic entry risk is legally high but commercially limited because the residual market is small.

FAQs

Is edrophonium chloride still FDA approved?

Historical FDA-approved injectable products exist, but individual products may be listed as discontinued. Discontinuation does not by itself establish withdrawal for safety or effectiveness reasons.

Is Tensilon still available in the United States?

Tensilon, the historical Roche brand, is no longer a dependable source of routine U.S. supply. Availability depends on remaining authorized products, wholesalers, hospital inventories, and specialty suppliers.

Does edrophonium chloride have patent protection?

The original active-ingredient protection is expired. No meaningful current patent estate is known to block broad generic manufacture of edrophonium chloride.

Can a generic company launch edrophonium chloride without a Paragraph IV lawsuit?

Potentially, if the applicable FDA approval pathway and reference-product requirements are satisfied. The absence of a strong active patent estate reduces litigation risk, but regulatory and manufacturing requirements remain.

Is edrophonium chloride commercially attractive for pharmaceutical investment?

Generally no. The product has low demand, limited pricing power, obsolete or reduced clinical applications, and sterile injectable manufacturing costs. Its value is primarily as a niche hospital-supply product rather than a growth asset.

References

1. U.S. Food and Drug Administration. (2015). Bridion (sugammadex) injection prescribing information. FDA.

2. U.S. Food and Drug Administration. (n.d.-a). Discontinued drug product list. FDA.

3. U.S. Food and Drug Administration. (n.d.-b). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. FDA.

4. National Library of Medicine. (n.d.). DailyMed: Edrophonium chloride injection labeling. U.S. National Library of Medicine.

5. U.S. Food and Drug Administration. (n.d.-c). Drugs@FDA: FDA-approved drugs database. FDA.