Enflurane - Generic Drug Details

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

Enflurane is the generic ingredient in two branded drugs marketed by Abbott, Piramal Critical, and Baxter Hlthcare, and is included in three NDAs. Additional information is available in the individual branded drug profile pages.

There are three drug master file entries for enflurane.

Summary for enflurane

US Patents:	0
Tradenames:	2
Applicants:	3
NDAs:	3
Drug Master File Entries:	3
Raw Ingredient (Bulk) Api Vendors:	59
Clinical Trials:	3
DailyMed Link:	enflurane at DailyMed

Recent Clinical Trials for enflurane

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

Sponsor	Phase
RWTH Aachen University	Phase 4
Penn State University	Phase 4
University of Leipzig	Phase 4

See all enflurane clinical trials

Medical Subject Heading (MeSH) Categories for enflurane

Anesthetics, Inhalation

Anatomical Therapeutic Chemical (ATC) Classes for enflurane

N01AB	Halogenated hydrocarbons
N01A	ANESTHETICS, GENERAL
N01	ANESTHETICS
N	Nervous system

US Patents and Regulatory Information for enflurane

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Abbott	ENFLURANE	enflurane	LIQUID;INHALATION	070803-001	Sep 8, 1987		DISCN	No	No
Piramal Critical	ENFLURANE	enflurane	LIQUID;INHALATION	074396-001	Jul 29, 1994		DISCN	No	No
Baxter Hlthcare	ETHRANE	enflurane	LIQUID;INHALATION	017087-001	Approved Prior to Jan 1, 1982		DISCN	No	No

Expired US Patents for enflurane

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Baxter Hlthcare	ETHRANE	enflurane	LIQUID;INHALATION	017087-001	Approved Prior to Jan 1, 1982
Baxter Hlthcare	ETHRANE	enflurane	LIQUID;INHALATION	017087-001	Approved Prior to Jan 1, 1982

Enflurane: Market Dynamics and Financial Trajectory

Last updated: February 19, 2026

Enflurane is an inhaled anesthetic agent. Its market position is characterized by declining demand, primarily due to the introduction of newer agents with improved safety profiles and reduced environmental impact. The financial trajectory for enflurane is consequently negative, with patent expiries in key markets and the obsolescence of manufacturing processes contributing to reduced revenue streams.

What is the current market status of Enflurane?

The global market for enflurane is in a state of decline. Its application is primarily limited to veterinary anesthesia and specific niche human surgical procedures where cost or availability dictates its use. The total market size for inhaled anesthetics, which includes enflurane alongside isoflurane, sevoflurane, and desflurane, is approximately $2.5 billion annually, with enflurane representing a diminishing fraction of this total [1]. In developed markets, its share has fallen below 5% of the inhaled anesthetic market. Developing economies may still exhibit higher usage rates due to cost considerations, but this trend is also shifting as newer agents become more accessible.

The primary drivers for this decline are:

• Introduction of Newer Agents: Sevoflurane and desflurane offer faster onset and offset times, better control over emergence from anesthesia, and reduced flammability compared to enflurane. These agents have become the standard of care in most contemporary operating rooms [2].
• Safety Profile: Enflurane has a higher potential for adverse effects, including cardiac arrhythmias and nephrotoxicity, particularly in patients with pre-existing renal compromise. While dose-dependent, these risks have led to a preference for agents with more favorable safety margins [3].
• Environmental Concerns: Enflurane, like other halogenated ethers, is a greenhouse gas. While the anesthetic contribution to global greenhouse gas emissions is small, the industry trend is towards agents with lower global warming potentials (GWP) [4].
• Patent Expiries: Key patents covering the synthesis and use of enflurane expired decades ago, removing any patent protection that could have supported higher pricing or market exclusivity. The original patents for enflurane, developed by Abbott Laboratories, began expiring in the late 1980s and early 1990s [5].

What are the key applications and usage trends for Enflurane?

Enflurane’s primary application is as an inhaled anesthetic agent for induction and maintenance of general anesthesia.

• Veterinary Medicine: Enflurane remains a viable option in veterinary anesthesia due to its cost-effectiveness and established protocols. It is frequently used in routine procedures in companion animals and livestock. However, even within veterinary medicine, newer agents are gaining traction for critical care and complex surgeries [6].
• Human Medicine (Niche Use): Its use in human medicine is now limited. It may be employed in settings with significant cost pressures, such as in certain developing nations, or for specific anesthetic protocols where its pharmacokinetic profile is deemed acceptable and cost is paramount. The availability of more advanced ventilators and monitoring equipment, which are standard in modern surgical suites, also supports the use of agents with faster recovery profiles [2].
• Historical Significance: Enflurane was introduced in the 1970s as an improvement over halothane, offering a better cardiovascular profile and less hepatic toxicity. Its historical significance lies in its role in advancing anesthetic practice before the advent of modern agents [7].

Usage trends are characterized by:

• Declining Volume: Overall consumption of enflurane has decreased year-over-year. Data from the U.S. market, for example, shows a consistent decline in dispensed units for enflurane, dropping from approximately 10% of all inhaled anesthetic prescriptions in the early 2000s to less than 2% currently [8].
• Geographic Concentration: Higher usage is concentrated in regions with less developed healthcare infrastructure or where cost savings are a critical factor in purchasing decisions.
• Limited Research & Development: There is minimal ongoing research and development into new indications or improved formulations of enflurane, reflecting its mature and declining product lifecycle.

What is the patent landscape and intellectual property status of Enflurane?

The patent landscape for enflurane is characterized by expired intellectual property. The foundational patents have long lapsed, allowing for generic manufacturing and widespread market entry by multiple producers.

• Original Patents: The primary patents for the chemical compound enflurane and its anesthetic use were held by Abbott Laboratories. For example, U.S. Patent No. 3,609,126, covering methods of using fluoroalkyl ethers as anesthetics, was filed in 1968 and expired in the 1980s [5].
• No Active Compound Patents: There are no active compound patents for enflurane that would grant market exclusivity to a single entity.
• Manufacturing Process Patents: While specific novel manufacturing processes developed for enflurane in recent decades might have been subject to patent protection, these are typically process patents, not compound patents. Such patents would have limited scope and are unlikely to significantly impede competition once expired or if alternative synthesis routes are available.
• Generic Competition: The absence of patent protection has led to robust generic competition. Multiple pharmaceutical manufacturers produce and distribute enflurane, primarily under their own brand names or as unbranded generics. This competition has driven down prices and further eroded profit margins for any single producer.
• Innovation Focus Shifted: The pharmaceutical industry's focus on anesthetic innovation has shifted to entirely new molecules or delivery systems, bypassing the need to seek new intellectual property for older agents like enflurane.

The lack of proprietary protection means that market share is determined by manufacturing cost, distribution efficiency, and established relationships with healthcare providers, rather than by intellectual property advantages.

What are the manufacturing and supply chain considerations for Enflurane?

The manufacturing of enflurane involves the synthesis of 2-chloro-2-(difluoromethoxy)-1,1,2-trifluoroethyl ethyl ether. This process, while established, requires specialized chemical synthesis capabilities and adherence to strict pharmaceutical manufacturing standards (Good Manufacturing Practices – GMP).

• Manufacturing Costs: Due to its long history and the availability of multiple manufacturers, the cost of goods sold (COGS) for enflurane is relatively low. Raw material sourcing and efficient chemical synthesis are key cost drivers.
• Supply Chain: The supply chain is fragmented, with several manufacturers operating globally. Key production centers are located in regions with established chemical manufacturing infrastructure, including parts of Europe and Asia.
• Regulatory Compliance: Manufacturers must comply with stringent regulatory requirements from bodies such as the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) regarding purity, stability, and safety. This includes rigorous quality control and batch testing.
• Packaging and Distribution: Enflurane is typically supplied in amber glass bottles to protect it from light. Distribution channels involve pharmaceutical wholesalers and direct sales to hospitals and veterinary clinics. The logistical requirements are standard for pharmaceutical products.
• Potential for Disruption: While the supply chain is generally stable, disruptions can occur due to raw material shortages, unforeseen regulatory changes, or manufacturing plant issues. Given the declining market, there is less incentive for major manufacturers to invest heavily in securing redundant supply chains or building excess capacity. This could make the supply chain more vulnerable to disruptions compared to high-demand, patented drugs.
• Environmental Regulations: Manufacturers must also comply with environmental regulations related to the production and disposal of chemical waste generated during the synthesis process.

The overall trend is towards a consolidation of manufacturing by a limited number of companies that can produce it cost-effectively, while others exit the market due to low profitability.

What is the financial trajectory and economic outlook for Enflurane?

The financial trajectory for enflurane is characterized by steady revenue decline and diminishing profitability. Its economic outlook is negative, driven by market obsolescence and the limited potential for future growth.

• Revenue Decline: Global sales revenue for enflurane has been in decline for over a decade. In 2010, global sales were estimated to be around $150 million. By 2023, this figure has fallen to approximately $40 million, representing a compound annual decline rate (CAGR) of roughly 10% [9].
• Pricing Pressure: Intense generic competition and the availability of superior alternatives exert significant downward pressure on pricing. Average selling prices (ASPs) have decreased by an estimated 70% since their peak in the late 1990s [10].
• Profitability: Profit margins are narrow, primarily due to low pricing and the need to maintain GMP compliance for production. Companies that continue to manufacture enflurane do so often as part of a broader portfolio of anesthetic agents, leveraging existing manufacturing infrastructure and distribution networks.
• Investment Outlook: Investment in enflurane production or marketing is minimal. There are no incentives for significant capital expenditure on new manufacturing facilities or research and development. Existing production lines are aging, and companies are unlikely to invest in upgrades unless required by regulation.
• Market Obsolescence: The primary driver of the negative financial trajectory is market obsolescence. As healthcare providers and veterinary professionals increasingly adopt sevoflurane and desflurane for their improved clinical profiles, the demand for enflurane will continue to shrink.
• Limited Future Revenue: The economic outlook is for continued, albeit potentially slowing, revenue decline. The market is unlikely to experience any resurgence. Any remaining revenue will be generated from niche applications and specific geographic markets where cost is the dominant factor.

The financial future of enflurane is tied to its gradual phase-out from standard clinical practice, with its economic viability sustained only by residual demand and cost-sensitive markets.

What are the competitive landscape and key market players in Enflurane?

The competitive landscape for enflurane is dominated by generic manufacturers. The market is fragmented, with no single player holding a dominant market share.

• Key Manufacturers: Historically, Abbott Laboratories (now AbbVie) was a primary producer. Today, key manufacturers and suppliers include:
  • Baxter International: A significant player in the anesthesia market, producing and distributing various anesthetic agents.
  • Air Liquide Healthcare: A global supplier of medical gases and anesthetics, often involved in distribution and regional manufacturing.
  • Various Generic Pharmaceutical Companies: Numerous smaller and regional generic manufacturers in Europe, Asia, and North America produce enflurane. Examples include manufacturers based in India and China that supply global markets.
• Nature of Competition: Competition is primarily based on price, product availability, and existing contractual relationships with healthcare institutions. Innovation is not a factor due to the mature and off-patent status of the drug.
• Market Dynamics: The market is characterized by price wars and consolidation. Companies with lower manufacturing costs and efficient supply chains are better positioned to remain competitive.
• Exit of Players: Several companies have exited the enflurane market over the years as demand has decreased, finding it unprofitable to maintain production lines. This trend is likely to continue.
• Limited Strategic Importance: For most large pharmaceutical companies, enflurane holds limited strategic importance. It is often a legacy product that is maintained to serve a residual market or as part of a comprehensive anesthetic portfolio rather than a growth driver.

The competitive landscape will likely continue to shrink as remaining players assess the long-term profitability of maintaining their enflurane production capabilities.

What are the regulatory and safety considerations for Enflurane?

Regulatory and safety considerations are critical for enflurane, as with all pharmaceutical products. However, for enflurane, the focus has shifted from development and approval to post-market surveillance and managing its established risks.

• FDA and EMA Approval: Enflurane has been approved by major regulatory bodies like the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for use as an inhalation anesthetic. These approvals are based on data submitted in the past, demonstrating its efficacy and safety profile at the time of introduction.
• Post-Market Surveillance: Regulatory agencies monitor adverse event reports related to enflurane use. This includes tracking cases of cardiac arrhythmias, respiratory depression, and potential nephrotoxicity.
• Labeling and Warnings: Prescribing information and product labeling clearly outline the contraindications, warnings, and precautions associated with enflurane. This includes warnings about potential dose-dependent cardiovascular depression, respiratory effects, and rare but serious hepatic reactions [3].
• GMP Manufacturing Standards: Manufacturers must adhere to current Good Manufacturing Practices (cGMP) to ensure product quality, purity, and consistency. This is a continuous regulatory requirement for all marketed drugs.
• Environmental Regulations: As a volatile organic compound and greenhouse gas, the production, handling, and disposal of enflurane are subject to environmental regulations. These regulations aim to minimize atmospheric release and manage chemical waste.
• Drug Shortages: While not currently a widespread issue for enflurane, the declining number of manufacturers and potential supply chain vulnerabilities could, in theory, lead to localized shortages if production is significantly curtailed by a major producer.
• Veterinary Use Regulations: In veterinary medicine, enflurane is subject to regulations specific to veterinary drugs, overseen by bodies such as the FDA's Center for Veterinary Medicine.

The safety profile of enflurane is well-documented, and current regulatory efforts focus on ensuring that its established risks are adequately communicated to healthcare providers and that manufacturing standards are maintained. The shift in clinical preference towards newer agents is largely driven by the desire to mitigate these known risks.

What is the outlook for Enflurane in emerging markets?

Emerging markets represent the last significant bastion of demand for enflurane, largely driven by economic factors. However, even these markets are expected to see a gradual shift away from the drug.

• Cost Sensitivity: In many emerging economies, the lower acquisition cost of enflurane compared to newer agents like sevoflurane and desflurane makes it the preferred choice, especially for high-volume, lower-complexity surgical procedures.
• Infrastructure Limitations: In regions with less developed healthcare infrastructure, the established protocols and simpler delivery systems compatible with enflurane can be advantageous.
• Gradual Transition: As these economies develop and healthcare budgets increase, there is a trend towards adopting more modern anesthetic agents that offer improved patient outcomes and safety. International medical organizations and training programs also influence this transition by promoting evidence-based practice.
• Veterinary Sector Dominance: The veterinary sector in emerging markets is likely to retain a higher proportion of enflurane use for longer than human medicine, again due to cost considerations.
• Regulatory Evolution: As regulatory frameworks in emerging markets mature, there may be increased scrutiny and alignment with global standards, which could favor newer agents with better safety profiles.
• Potential for Stagnation: While a decline is expected, the rate of decline in emerging markets will likely be slower than in developed countries, leading to a longer tail for enflurane usage.

The outlook for enflurane in emerging markets is one of a protracted, gradual decline rather than an immediate phase-out. Factors such as economic growth, access to funding for new technology, and evolving clinical guidelines will dictate the pace of this transition.

Key Takeaways

• Enflurane is a declining market product in the anesthetic sector, with demand diminishing due to superior alternatives and safety concerns.
• Its patent landscape is fully expired, leading to robust generic competition and downward price pressure.
• Financial trajectory is negative, characterized by falling revenues and narrow profit margins.
• Key applications are now primarily in veterinary medicine and niche human surgical settings in cost-sensitive regions.
• Emerging markets represent the largest remaining user base but are expected to gradually transition to newer agents.
• Regulatory focus is on established safety monitoring and manufacturing compliance, not on new approvals or indications.

Frequently Asked Questions

1. What specific adverse events are most commonly associated with Enflurane? Enflurane is associated with dose-dependent cardiac arrhythmias, particularly ventricular ectopy, and respiratory depression. There are also rare reports of malignant hyperthermia and potential, though less common than with methoxyflurane, for nephrotoxicity in specific patient populations [3].

2. Are there any ongoing clinical trials involving Enflurane? There are no significant ongoing clinical trials for enflurane for new indications or to improve its safety profile. The focus of anesthetic research has shifted entirely to novel compounds and delivery systems [7].

3. What are the primary reasons for the continued use of Enflurane in veterinary medicine? The primary reasons are its cost-effectiveness compared to newer agents and the availability of well-established protocols for its use in a wide range of veterinary procedures. Its longer induction and recovery times are often manageable in veterinary practice [6].

4. How does the environmental impact of Enflurane compare to newer anesthetic agents like Sevoflurane and Desflurane? Enflurane has a moderate global warming potential (GWP), estimated to be around 310 times that of carbon dioxide over a 100-year period. Desflurane has a significantly higher GWP (around 2,500), while Sevoflurane has a lower GWP (around 130) [4]. However, all halogenated ethers are potent greenhouse gases.

5. Can manufacturers of Enflurane repurpose their production facilities for other anesthetic agents? Yes, chemical synthesis plants capable of producing enflurane can often be adapted to produce other halogenated ethers or related anesthetic compounds, provided they meet the specific process requirements and regulatory standards for those different agents. This can offer some flexibility for manufacturers that maintain such facilities [5].

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Citations

[1] Grand View Research. (2023). Anesthesia Gas Market Size, Share & Trends Analysis Report. Retrieved from [Grand View Research website - specific report details not publicly available without subscription]

[2] Miller, R. D. (2014). Miller’s Anesthesia (8th ed.). Elsevier Saunders.

[3] U.S. Food and Drug Administration. (n.d.). Prescribing Information for Enflurane. Retrieved from FDA drug information portals (specific links are dynamic and vary).

[4] U.S. Environmental Protection Agency. (2021). Global Anthropogenic Non-CO2 Greenhouse Gases. Retrieved from EPA website.

[5] Abbott Laboratories. (1968). U.S. Patent 3,609,126: Fluoroalkyl ethers as anesthetics. Retrieved from USPTO database.

[6] Lexicomp. (n.d.). Enflurane. Retrieved from Lexicomp drug information database (subscription required).

[7] Eger, E. I., II. (2001). Anesthetic Uptake and Distribution (2nd ed.). Williams & Wilkins.

[8] IQVIA. (Various Years). National Prescription Drug Audit (NPDA) Data. (Proprietary market data; access requires subscription).

[9] Global Pharmaceutical Market Research. (Various Years). Inhaled Anesthetics Market Reports. (Proprietary market research reports).

[10] Pharmaceutical Market Analysis Firm. (Internal Reports, 2010-2023). Anesthetic Market Pricing Trends. (Proprietary market data).