Last updated: July 31, 2026
Alfentanil hydrochloride is an established short-acting synthetic opioid used primarily as an intravenous anesthetic adjunct. Its commercial profile is mature and genericized: no meaningful originator exclusivity remains, clinical research mainly evaluates alfentanil as a comparator or anesthetic technique component, and market growth depends on hospital procedure volumes, supplier continuity, controlled-substance regulation, and substitution by remifentanil, fentanyl, and other perioperative agents.
What is alfentanil hydrochloride used for?
Alfentanil hydrochloride is an intravenous opioid analgesic with rapid onset and short duration. In the United States, the approved product is indicated for use as an analgesic adjunct during anesthesia, for induction of anesthesia, and for maintenance of anesthesia when administered by trained professionals in appropriately monitored settings (FDA, 2023).
| Attribute |
Alfentanil hydrochloride |
| Pharmacologic class |
Synthetic opioid analgesic |
| Primary receptor |
Mu-opioid receptor agonist |
| Route |
Intravenous |
| Common concentration |
500 mcg/mL injection |
| Typical setting |
Operating rooms, procedural anesthesia, monitored anesthesia care |
| Controlled-substance status |
Schedule II in the United States |
| Originator product |
Alfenta |
| Current commercial model |
Generic injectable hospital product |
| Main competitors |
Fentanyl, remifentanil, sufentanil, morphine and other anesthetic adjuncts |
| Primary commercial risk |
Supply interruption and substitution rather than patent expiry |
Alfentanil has a faster onset than fentanyl because of its pharmacokinetic profile and relatively low ionization at physiologic pH. Its clinical use is constrained by respiratory depression, chest-wall rigidity, bradycardia, hypotension, nausea, vomiting, and the need for airway and ventilatory support (FDA, 2023).
What is the FDA regulatory status of alfentanil hydrochloride?
Alfentanil hydrochloride is an FDA-approved injectable drug. The original U.S. product, Alfenta, was approved under NDA 018610. Current U.S. products are marketed as generic alfentanil hydrochloride injection under abbreviated or supplemental regulatory pathways, depending on the manufacturer and product history.
The product is not a new molecular entity and does not have current regulatory exclusivity comparable to a recently approved drug. Its regulatory value is concentrated in established manufacturing capability, sterile injectable compliance, controlled-substance handling, and hospital formulary access.
FDA regulatory characteristics
| Regulatory issue |
Status |
| FDA approval |
Yes |
| New molecular entity exclusivity |
Expired |
| Pediatric exclusivity |
No current commercially relevant exclusivity identified |
| Orphan-drug exclusivity |
No |
| Biosimilar pathway |
Not applicable |
| Generic pathway |
Applicable |
| Controlled-substance requirements |
Extensive |
| Sterile injectable requirements |
Extensive |
| Drug shortage exposure |
Material for some suppliers and presentations |
Alfentanil is subject to opioid-related manufacturing quotas, recordkeeping, security, distribution controls, and postmarketing obligations. These requirements can restrict the number of active suppliers even when no patent barrier exists.
What clinical trials are evaluating alfentanil hydrochloride?
Alfentanil is primarily used in clinical research as an established anesthetic comparator, analgesic control, or pharmacologic probe. It is not generally being developed as a new commercial drug candidate.
Clinical studies involving alfentanil have historically examined:
- Opioid dose-response relationships.
- Induction and maintenance of general anesthesia.
- Procedural sedation.
- Hemodynamic responses to intubation.
- Respiratory depression and recovery profiles.
- Pharmacokinetics in adults and pediatric populations.
- Comparisons with remifentanil, fentanyl, sufentanil, and other anesthetics.
- Neurophysiologic and pain-response testing.
- Opioid-induced hyperalgesia and tolerance.
- Use in short-duration surgical and diagnostic procedures.
The commercial implication is important: clinical-trial activity does not translate directly into a new alfentanil market indication. Most studies use the drug as a known comparator or research tool rather than seeking a new composition, formulation, or therapeutic label.
Clinical development outlook
No conventional late-stage development program comparable to those for new opioid formulations is associated with alfentanil hydrochloride. The relevant clinical evidence base is mature and supports perioperative use, but the drug has limited development momentum because:
- Its approved use is well established.
- Multiple low-cost opioid alternatives are available.
- Generic injectable economics provide limited return on large clinical programs.
- New opioid development faces substantial abuse-deterrence, respiratory-safety, and regulatory requirements.
- Hospital adoption depends more on supply reliability and anesthesia protocols than on new efficacy data.
How does alfentanil compare with fentanyl and remifentanil?
Alfentanil competes on onset, offset, titratability, and recovery profile. It does not lead the market on volume or clinical familiarity.
| Drug |
Relative onset |
Duration profile |
Main advantage |
Main limitation |
| Alfentanil |
Rapid |
Short |
Fast onset and controllable intraoperative analgesia |
Respiratory depression; limited routine use |
| Fentanyl |
Rapid |
Intermediate |
Broad availability, low cost, extensive familiarity |
Longer residual effect than remifentanil |
| Remifentanil |
Very rapid |
Ultra-short, context-sensitive |
Precise titration and rapid recovery |
Higher cost; infusion dependence |
| Sufentanil |
Rapid |
Longer than alfentanil |
High potency and established cardiac-anesthesia use |
Prolonged respiratory and recovery effects |
| Morphine |
Slower |
Longer |
Low cost and broad postoperative use |
Slower onset and less predictable recovery |
Alfentanil is most commercially relevant where rapid onset and relatively short recovery are valuable but remifentanil cost, infusion requirements, or institutional protocols favor an alternative.
What patents protect alfentanil hydrochloride?
No meaningful composition-of-matter patent protection remains for alfentanil hydrochloride. The drug was discovered and commercialized decades ago, and any original compound, formulation, and product patents have expired.
| Patent category |
Current status |
Commercial relevance |
| Alfentanil molecule |
Expired |
None |
| Original injectable formulation |
Expired |
None |
| Original product patents |
Expired |
None |
| New salt or polymorph protection |
No material protection identified |
Low |
| Modern delivery-system patents |
No established market-blocking estate identified |
Low |
| Method-of-use patents |
No meaningful blocking estate identified |
Low |
| Manufacturing patents |
Potentially relevant as confidential know-how |
Supplier-specific |
The principal barriers to entry are regulatory and operational rather than patent-based. A prospective manufacturer must demonstrate drug substance quality, sterile manufacturing controls, container-closure integrity, stability, bioequivalence or other applicable requirements, controlled-substance compliance, and reliable distribution.
When does alfentanil lose exclusivity?
Alfentanil lost meaningful market exclusivity years ago. The originator product, Alfenta, is no longer protected by a commercially relevant patent estate or regulatory exclusivity period.
Generic entry therefore does not depend on a future patent expiration date. Entrants can compete when they obtain regulatory approval, establish an adequate controlled-substance quota, and qualify for hospital and wholesaler distribution.
Paragraph IV challenge risk
Paragraph IV litigation risk is low because the relevant patents have expired or have no apparent market-blocking role. A new generic applicant is more likely to face:
- FDA review questions.
- Manufacturing inspection issues.
- Controlled-substance quota limitations.
- Product-quality or stability concerns.
- Commercial contracting barriers.
- Shortage-driven supply volatility.
The absence of patent litigation does not eliminate launch risk. Sterile injectable products often have fewer reliable suppliers than oral generics, and an approved product may still lack commercial scale.
What is the Orange Book status of alfentanil hydrochloride?
The Orange Book status of alfentanil hydrochloride is that of an established prescription injectable with generic competition and no current originator exclusivity of commercial significance. Orange Book-listed patents, if any historical listings remain associated with the reference product, do not create a practical forward-looking barrier equivalent to an unexpired composition or formulation patent.
The product’s Orange Book relevance is therefore primarily regulatory:
- Reference-listed-drug identification.
- Approved dosage form and strength.
- Therapeutic-equivalence assessments for approved generic products.
- Historical patent and exclusivity records.
- Product-specific labeling and safety information.
What patent litigation affects alfentanil hydrochloride?
No material active patent litigation is associated with alfentanil hydrochloride as a commercial product. The drug’s litigation exposure is more likely to arise from product liability, controlled-substance distribution, manufacturing quality, or procurement disputes than from patent enforcement.
A future patent dispute would require a new entrant to assert a non-obvious formulation, delivery system, manufacturing process, or use. Such a patent would need to provide a practical commercial advantage over the established injection and survive validity and infringement scrutiny. The probability of a broad blocking patent is low because the core molecule and conventional injectable presentation are long established.
What formulations are protected by alfentanil patents?
The conventional alfentanil hydrochloride injection is not protected by an active, commercially meaningful formulation patent estate. The marketed product generally consists of alfentanil hydrochloride in an aqueous injectable solution with excipients used to control pH, tonicity, stability, and compatibility.
Potential future formulation opportunities could include:
- Lower-concentration presentations for dosing flexibility.
- Preservative-free single-use containers.
- Ready-to-administer syringes.
- Closed-system delivery devices.
- Stability improvements for operating-room storage.
- Combination products for procedural anesthesia.
- Abuse-deterrent or tamper-resistant packaging.
These opportunities would require a clear clinical, operational, or regulatory benefit. A minor change to concentration or packaging would not necessarily create durable market protection.
How strong is the alfentanil patent estate?
The patent estate is weak for exclusivity purposes and irrelevant to most generic-entry decisions.
| Strength factor |
Assessment |
| Composition-of-matter protection |
None remaining |
| Formulation protection |
Weak or expired |
| Method-of-use protection |
Weak |
| Manufacturing protection |
Potentially meaningful only as trade secret or process know-how |
| Litigation deterrence |
Low |
| Generic-entry barrier |
Regulatory and operational |
| Lifecycle-management potential |
Limited |
The strongest defensible assets in this market are likely to be manufacturing reliability, supply contracts, validated sterile processes, and regulatory execution rather than patents.
What is the alfentanil hydrochloride market size and revenue outlook?
Public market data usually combines alfentanil with broader opioid analgesics, anesthetic agents, or hospital injectables. Standalone global revenue estimates are therefore difficult to validate and should not be treated as equivalent to audited product sales.
Alfentanil is a small hospital injectable market compared with fentanyl and remifentanil. Demand is driven by:
- Surgical procedure volumes.
- Use of general anesthesia and monitored anesthesia care.
- Hospital formulary preferences.
- Availability of competing opioids.
- Drug-shortage conditions.
- Controlled-substance procurement policies.
- Regional anesthesia practice.
- Generic supplier pricing.
Revenue exposure for a manufacturer is typically modest on a portfolio basis unless the company holds a strong hospital-distribution position or benefits from a competitor shortage. The product can still have strategic value because it fills a perioperative opioid category and may support broader institutional contracts.
Market projection, 2025-2030
The most defensible projection is a scenario range rather than a single market CAGR. A baseline index of 100 represents estimated 2025 alfentanil demand or revenue for a defined manufacturer or geographic market.
| Scenario |
2030 index versus 2025 |
Implied direction |
Main drivers |
| Downside |
75-85 |
Decline |
Substitution by remifentanil or fentanyl, formulary rationalization, supplier exit |
| Base case |
90-105 |
Flat to modest decline |
Stable procedure volumes offset by price pressure and substitution |
| Upside |
110-125 |
Moderate growth |
Supply shortages, additional generic entrants, recovery in elective surgery, broader procedural use |
The base case is flat to modestly negative in nominal product revenue because generic price competition can offset procedure growth. Volume may remain stable while revenue declines.
A stronger outcome requires either sustained shortages of competing opioids, improved supply reliability, or a differentiated presentation. A weaker outcome follows broader use of remifentanil for tightly controlled intraoperative infusions, substitution by fentanyl because of cost and familiarity, or loss of a specialist supplier.
Which companies compete in the alfentanil market?
Competition is fragmented across generic injectable manufacturers and regional distributors. The relevant competitive set can include companies such as Hikma Pharmaceuticals, Fresenius Kabi, Pfizer-linked injectable operations, and other approved generic suppliers, depending on country, presentation, and current commercial status.
Market share can change quickly because:
- The product is a low-volume injectable.
- Hospitals often purchase through group purchasing organizations.
- Controlled-substance quotas constrain supply.
- A single manufacturing interruption can shift orders to competitors.
- Product discontinuations can reduce the number of active suppliers.
The most important competitive metric is often available supply rather than nominal regulatory approval.
What manufacturing and intellectual-property barriers affect alfentanil?
Manufacturing barriers are more important than patent barriers. Alfentanil hydrochloride requires controlled handling of a potent opioid active pharmaceutical ingredient and sterile injectable production.
Key barriers include:
- Access to qualified alfentanil active pharmaceutical ingredient.
- DEA or equivalent controlled-substance permissions.
- Annual production and procurement quotas.
- Sterile filling and aseptic-process validation.
- Stability data for the final container.
- Container-closure and extractables testing.
- Validated analytical methods.
- Compliance with current good manufacturing practice.
- Secure warehousing and distribution.
- Hospital and wholesaler qualification.
A manufacturer with a technically simple product can still fail commercially if it cannot obtain sufficient quota, maintain sterile capacity, or secure predictable hospital distribution.
What generic launch scenarios exist for alfentanil?
Because patent barriers are minimal, generic launch scenarios depend on commercial discipline.
Low-cost commodity launch
A manufacturer enters with the conventional 500 mcg/mL injection and competes on price. This strategy faces limited market size, entrenched suppliers, and a risk that price reductions will not justify incremental manufacturing complexity.
Supply-security launch
A manufacturer positions the product as a reliable secondary source for hospitals and wholesalers. This strategy can gain value during shortages and may command better institutional acceptance than a purely price-based launch.
Differentiated presentation launch
A company develops prefilled syringes, ready-to-administer packaging, or a preservative-free presentation. Such a product may improve operating-room workflow but requires additional regulatory and validation work.
Portfolio-contract launch
A manufacturer includes alfentanil in a broader anesthesia portfolio containing fentanyl, remifentanil, sedatives, and local anesthetics. Contracting leverage is stronger than for a single low-volume product.
Are licensing deals relevant to alfentanil hydrochloride?
Licensing activity is likely to be limited. The molecule is generic, the originator patents are expired, and the addressable market is small. Commercial arrangements are more likely to involve:
- Contract manufacturing.
- Regional marketing rights.
- API supply agreements.
- Hospital-distribution contracts.
- Portfolio acquisitions.
- Product-transfer agreements.
- Co-marketing by generic injectable companies.
A licensing transaction would be more commercially rational for a differentiated delivery system or a broader anesthesia portfolio than for conventional alfentanil injection alone.
What is the biosimilar risk for alfentanil hydrochloride?
Biosimilar risk is not applicable. Alfentanil hydrochloride is a chemically synthesized small molecule, not a biologic. Competitive risk comes from ANDA-approved generics, branded generic injectables, alternative opioids, and non-opioid anesthesia protocols.
The principal substitution risks are:
- Fentanyl for lower cost and familiarity.
- Remifentanil for rapid titration and recovery.
- Sufentanil for potency and selected cardiac procedures.
- Non-opioid adjuncts that reduce opioid requirements.
- Regional or neuraxial anesthesia.
- Multimodal analgesia protocols.
Key Takeaways
- Alfentanil hydrochloride is an established FDA-approved intravenous opioid used mainly as an anesthetic adjunct.
- Its molecular, formulation, and originator exclusivity have expired.
- No material current patent litigation or Paragraph IV risk affects the product.
- Clinical trials mainly use alfentanil as a comparator, anesthetic component, or pharmacologic research tool.
- The market is small relative to fentanyl and remifentanil and is largely generic.
- A reasonable 2025-2030 base case is flat to modestly declining revenue, with a broad outcome range driven by supply and substitution.
- Sterile manufacturing, controlled-substance quotas, quality compliance, and hospital distribution are stronger barriers than intellectual property.
- The most attractive commercial strategy is a reliable supply or differentiated delivery product supported by a broader anesthesia portfolio.
Frequently Asked Questions
Is alfentanil hydrochloride still commercially available?
Yes. Availability depends on country, manufacturer, presentation, and current supply conditions. Hospital procurement should distinguish regulatory approval from active commercial distribution.
Is alfentanil stronger than fentanyl?
Alfentanil is potent and has rapid onset, but clinical potency comparisons depend on dose, administration rate, patient factors, and anesthetic context. It is generally selected for pharmacokinetic control rather than as a universal replacement for fentanyl.
Can a company obtain a new patent on alfentanil injection?
A company could seek patent protection for a genuinely novel formulation, device, manufacturing process, or use. A conventional alfentanil hydrochloride injection would face substantial novelty and obviousness challenges.
Is alfentanil used in pediatric anesthesia?
It has been studied and used in pediatric anesthesia under specialist supervision, but dosing and safety depend on age, weight, comorbidities, airway management, and institutional protocols.
What is the main investment risk in alfentanil?
The main risk is limited standalone market scale combined with generic pricing pressure. The principal upside is supply disruption affecting competing products or the ability to bundle alfentanil with a larger injectable anesthesia portfolio.
References
-
U.S. Food and Drug Administration. (2023). Alfentanil hydrochloride injection prescribing information. FDA.
-
U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations. FDA.
-
U.S. Drug Enforcement Administration. (2024). Controlled substances schedules. U.S. Department of Justice.
-
National Library of Medicine. (2024). DailyMed: Alfentanil hydrochloride injection. U.S. National Library of Medicine.
-
National Library of Medicine. (2024). ClinicalTrials.gov. U.S. National Library of Medicine.
