DIAMOX Drug Patent Profile

When do Diamox patents expire, and when can generic versions of Diamox launch?

Diamox is a drug marketed by Teva Branded Pharm and Teva Womens and is included in three NDAs.

The generic ingredient in DIAMOX is acetazolamide sodium. There are two drug master file entries for this compound. Six suppliers are listed for this compound. Additional details are available on the acetazolamide sodium profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Diamox

A generic version of DIAMOX was approved as acetazolamide sodium by HIKMA on February 28^th, 1995.

Summary for DIAMOX

US Patents:	0
Applicants:	2
NDAs:	3
Raw Ingredient (Bulk) Api Vendors:	94
Clinical Trials:	57
Patent Applications:	4,554
Drug Prices:	Drug price information for DIAMOX
DailyMed Link:	DIAMOX at DailyMed

See drug prices for DIAMOX

Recent Clinical Trials for DIAMOX

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

Sponsor	Phase
Prisma Health-Upstate	PHASE4
National Heart, Lung, and Blood Institute (NHLBI)	Phase 2
Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)	Phase 2

See all DIAMOX clinical trials

US Patents and Regulatory Information for DIAMOX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Teva Branded Pharm	DIAMOX	acetazolamide	CAPSULE, EXTENDED RELEASE;ORAL	012945-001	Approved Prior to Jan 1, 1982		DISCN	Yes	No
Teva Branded Pharm	DIAMOX	acetazolamide	TABLET;ORAL	008943-002	Approved Prior to Jan 1, 1982		DISCN	Yes	No
Teva Womens	DIAMOX	acetazolamide sodium	INJECTABLE;INJECTION	009388-001	Approved Prior to Jan 1, 1982		DISCN	Yes	No

DIAMOX (Acetazolamide) Market Dynamics, Patent Position, and Financial Trajectory

Last updated: October 5, 2026

DIAMOX is the legacy brand of acetazolamide, a carbonic anhydrase inhibitor used primarily for glaucoma, altitude sickness, edema, and selected seizure disorders. Its commercial position is no longer protected by meaningful patent exclusivity. The U.S. market is dominated by generic acetazolamide tablets, extended-release capsules, and injectable products. DIAMOX-related revenue is therefore difficult to isolate publicly and is unlikely to represent a material growth asset for the current rights holder.

What is DIAMOX and how is acetazolamide used?

DIAMOX contains acetazolamide, a sulfonamide derivative that inhibits carbonic anhydrase. The drug reduces aqueous humor production, increases renal bicarbonate excretion, and produces systemic metabolic effects that support its use across several indications.

Product form	Common strengths	Principal uses
Immediate-release tablets	125 mg, 250 mg	Glaucoma, edema, seizure disorders, altitude sickness
Extended-release capsules, historically marketed as DIAMOX Sequels	500 mg	Glaucoma, edema, selected neurological indications
Injection	500 mg vial in some markets	Acute-care and hospital use, including glaucoma and metabolic indications

The drug is administered orally for most outpatient uses. The injectable presentation is relevant to hospitals and acute-care settings but has a smaller commercial base than oral generic products.

What is the FDA regulatory status of DIAMOX?

Acetazolamide is an established FDA-approved active ingredient with decades of clinical use. The original DIAMOX brand entered the market long before the modern Hatch-Waxman framework and has no meaningful period of new-drug exclusivity remaining.

The FDA-approved product family has included:

• Immediate-release acetazolamide tablets
• Extended-release acetazolamide capsules
• Acetazolamide sodium for injection

The current U.S. market is primarily supplied through abbreviated new drug applications, or ANDAs, rather than through a commercially differentiated new-drug application. Generic products must demonstrate pharmaceutical equivalence and bioequivalence to the applicable reference product.

Is DIAMOX still marketed in the United States?

The availability of the DIAMOX name depends on dosage form, manufacturer, and distribution channel. Brand presentation has been inconsistent over time, while generic acetazolamide remains commercially available from multiple manufacturers.

The practical market distinction is:

1. DIAMOX is the legacy brand name.
2. Acetazolamide is the active pharmaceutical ingredient and dominant commercial product.
3. Generic supply, not brand promotion, determines most U.S. access and revenue.

FDA labeling and product availability should be reviewed by National Drug Code and dosage form because a brand label can remain in regulatory databases even when commercial distribution is limited or intermittent.[1]

What patents protect DIAMOX and acetazolamide?

No commercially relevant, unexpired U.S. patent estate is generally associated with the original acetazolamide molecule or its basic therapeutic uses. Acetazolamide was discovered and commercialized more than 70 years ago, placing the core composition-of-matter and early use rights well beyond their ordinary patent terms.

Patent category	DIAMOX position
Composition of matter	Expired
Original glaucoma uses	Expired
Original diuretic and seizure uses	Expired
Basic oral formulations	Expired or commercially irrelevant
Extended-release formulation rights	No established current exclusivity moat
Manufacturing patents	Potentially relevant to specific processes, but not a barrier to ordinary generic entry
Regulatory exclusivity	Expired

The absence of current core patents means that a new generic manufacturer generally does not face a branded patent barrier comparable to those associated with recently approved small-molecule drugs.

How strong is the DIAMOX patent estate?

The DIAMOX patent estate is weak from a market-exclusivity perspective. Its residual defensibility, if any, would arise from manufacturing know-how, supply contracts, regulatory history, product quality, or distribution rather than from enforceable composition or method-of-use patents.

Any later-filed patents covering a specific formulation, manufacturing process, or delivery system would need to be assessed separately. Such patents would not restore exclusivity over ordinary immediate-release acetazolamide tablets.

When does DIAMOX lose exclusivity?

DIAMOX lost effective market exclusivity decades ago. The commercially relevant exclusivity event was the expiration of the original patent and regulatory protection surrounding acetazolamide, not a future loss date.

Exclusivity element	Estimated status
Original active-ingredient patent	Expired decades ago
Original FDA exclusivity	Expired
Generic entry	Established
Current brand protection	No material protection identified
Future loss-of-exclusivity event	None of commercial significance

The product should be analyzed as a mature generic market rather than as a branded drug approaching loss of exclusivity.

What is the Orange Book status of DIAMOX?

The Orange Book may contain reference-listed-drug records for acetazolamide products, including historical brand or reference products. An Orange Book listing does not establish current commercial importance or an active patent barrier.

For DIAMOX, the key conclusion is that the product does not have the type of unexpired listed-patent estate that would normally support a meaningful Paragraph IV litigation strategy. Any current Orange Book record should be checked at the specific product level because tablet, extended-release, and injectable presentations may have separate listings or reference-product histories.[2]

Are there Paragraph IV challenges to DIAMOX?

Generic acetazolamide has already entered the market, so Paragraph IV challenges are not the principal competitive issue. A new ANDA applicant could still certify against listed patents if an applicable reference product carried active patents, but the economic value of such litigation would be limited unless the product targeted a protected formulation or a supply-constrained presentation.

The more relevant entry questions are:

• Whether the proposed product is therapeutically and pharmaceutically equivalent
• Whether the dosage form has reliable commercial supply
• Whether the applicant can obtain adequate raw material
• Whether the product is subject to a temporary FDA shortage
• Whether the applicant can secure hospital or wholesaler contracts

What formulations are protected by DIAMOX patents?

The economically important formulation distinction is between immediate-release acetazolamide and extended-release acetazolamide.

Immediate-release tablets are highly commoditized. Extended-release capsules historically offered greater product differentiation, but age alone does not create current patent protection. A formulation patent would need to remain unexpired and be listed or enforceable against the relevant product. No broad, commercially decisive DIAMOX formulation barrier is apparent from the product’s mature generic market position.

Does DIAMOX Sequels have separate protection?

DIAMOX Sequels, the extended-release presentation, could have had formulation-specific intellectual-property rights during its development and commercialization. Those rights would now be expected to be expired or commercially immaterial given the product’s age and the existence of generic acetazolamide extended-release products or substitutes in relevant markets.

The residual advantage of an extended-release product is operational rather than legal:

• Reduced dosing frequency
• Established clinician familiarity
• Potential preference in selected patients
• Distribution relationships
• Manufacturing capability for a technically more complex dosage form

Which companies compete with DIAMOX?

The competitive field consists mainly of generic manufacturers and contract suppliers. Market participation varies by dosage form and country.

Potential U.S. competitors and suppliers have included companies such as:

• Teva Pharmaceuticals
• Hikma Pharmaceuticals
• Rising Pharmaceuticals
• Zydus Pharmaceuticals
• AvKARE and other institutional suppliers
• Regional and contract manufacturers supplying acetazolamide under private labels

The relevant competitor set changes with product availability, FDA approvals, wholesaler contracts, and shortage conditions. Acetazolamide is not a conventional branded market in which promotional share determines performance. The principal competitive variables are price, fill rate, manufacturing continuity, and channel access.

What is the financial trajectory of DIAMOX?

No widely reported public financial statement isolates DIAMOX revenue from the broader portfolios of its owner, distributor, or generic supplier. The financial trajectory is therefore best assessed through market structure rather than a standalone reported sales series.

Historical trajectory

DIAMOX followed the standard lifecycle of a legacy small-molecule drug:

1. High-value branded sales during the protected period.
2. Generic entry after patent and exclusivity expiry.
3. Rapid erosion of branded pricing and market share.
4. Stabilization as a low-cost essential medicine.
5. Periodic revenue volatility caused by supply shortages and manufacturer exits.

The product’s current economic value is concentrated in volume and supply reliability, not in premium pricing.

Current revenue characteristics

Acetazolamide demand is relatively durable because the drug remains clinically useful for several indications and has few direct low-cost substitutes for every use. Revenue growth is constrained by:

• Low generic prices
• Multiple approved suppliers
• Limited promotional spending
• Pharmacy and hospital purchasing pressure
• Reimbursement controls
• Substitution among manufacturers

Temporary shortages can raise realized prices, but shortage-driven revenue increases are unstable and may attract new entrants or additional production.

Financial driver	Effect on DIAMOX economics
Generic competition	Compresses price and gross margin
Stable clinical demand	Supports recurring unit volume
Shortages	Can increase prices temporarily
Low manufacturing complexity for tablets	Limits long-term pricing power
Extended-release manufacturing	Creates modest supply differentiation
Hospital procurement	Increases price pressure
Brand recognition	Provides limited advantage without premium reimbursement

Revenue exposure for manufacturers

For a diversified pharmaceutical company, acetazolamide is generally a small portfolio product. Its strategic value can be higher than its absolute revenue when it:

• Fills a hospital formulary need
• Supports a broader generic portfolio
• Benefits from a temporary competitor shortage
• Uses existing manufacturing capacity
• Provides stable low-volatility unit demand

A company dependent on acetazolamide alone would face high exposure to price erosion, procurement losses, regulatory manufacturing findings, and supply interruptions.

How do shortages affect the acetazolamide market?

Shortage risk is more important than patent risk. Mature generic products can become supply constrained when several low-margin manufacturers reduce production, encounter quality problems, or lose access to active pharmaceutical ingredient.

Shortage effects include:

• Allocation by wholesalers
• Higher spot prices
• Pharmacy substitution across manufacturers
• Greater hospital purchasing activity
• Increased value of reliable inventory
• Temporary entry incentives for additional suppliers

FDA and ASHP shortage records should be reviewed by presentation because oral tablets, extended-release capsules, and injectable acetazolamide can have different supply conditions.[3,4]

A shortage does not create intellectual-property exclusivity. It creates a temporary commercial advantage for suppliers with available inventory and acceptable regulatory status.

What patent litigation affects DIAMOX?

DIAMOX is not generally associated with active high-value patent litigation comparable to newer branded medicines. The core commercial disputes, where they arise, are more likely to involve:

• Generic product quality
• Manufacturing compliance
• Supply contracts
• Distributor allocation
• Trademark use
• Product liability
• Shortage-related purchasing

The litigation risk from a new acetazolamide entrant is therefore more likely to be regulatory and operational than patent-driven. A company developing an extended-release version would face greater formulation and bioequivalence execution risk than an immediate-release tablet applicant.

Are there licensing deals for DIAMOX?

No major current licensing transaction is central to the commercial valuation of DIAMOX. Historical rights may have moved through acquisitions, product divestitures, or generic portfolio transactions, but the molecule is not generally treated as a high-value partnered asset.

Potential transaction value would be based on:

• Product registrations
• Approved dosage forms
• Manufacturing rights
• Geographic distribution
• Existing hospital contracts
• Supply continuity
• Inventory position

A transaction involving acetazolamide would normally be evaluated as a mature generic asset or portfolio add-on rather than as an innovative-drug licensing opportunity.

How does DIAMOX compare with competing carbonic anhydrase inhibitors?

DIAMOX has a distinct position because acetazolamide is systemic and inexpensive, while other carbonic anhydrase inhibitors may be topical or used in narrower settings.

Product or class	Primary role	Commercial relationship to acetazolamide
Acetazolamide	Systemic carbonic anhydrase inhibition	Core low-cost comparator
Dorzolamide	Topical glaucoma therapy	Competes mainly in ophthalmology
Brinzolamide	Topical glaucoma therapy	Alternative for ocular pressure reduction
Methazolamide	Systemic carbonic anhydrase inhibitor	Narrower systemic alternative
Mannitol and other agents	Acute pressure or edema management	Indication-specific alternatives

Acetazolamide remains difficult to displace where systemic carbonic anhydrase inhibition is required and cost is important. It is more vulnerable in chronic glaucoma treatment when topical agents provide adequate efficacy with fewer systemic effects.

What generic launch scenarios exist for DIAMOX?

Because the market is already generic, future launch scenarios concern additional suppliers, dosage forms, and geographic expansion rather than first generic entry.

Immediate-release tablet launch

This is the lowest-barrier scenario. The applicant would face strong price competition and limited differentiation. Commercial success would depend on low manufacturing cost, reliable supply, and pharmacy-channel access.

Extended-release launch

This offers more differentiation but requires more demanding formulation development, dissolution control, stability work, and bioequivalence execution. The addressable market is smaller than for standard tablets.

Injectable launch

An injectable product can benefit from hospital demand and shortage conditions, but it carries higher manufacturing, sterility, quality-control, and regulatory risks.

Geographic expansion

Outside the United States, demand is influenced by national reimbursement, hospital procurement, local registration requirements, and distributor networks. Patent freedom generally does not eliminate regulatory or market-access barriers.

What manufacturing and intellectual-property barriers exist?

The main barriers are operational:

• Consistent acetazolamide active pharmaceutical ingredient supply
• Control of tablet and capsule dissolution
• Stability and packaging
• Injectable sterility assurance
• FDA inspection readiness
• Reliable batch release
• Wholesale distribution
• Shortage-response capacity

Immediate-release tablets are relatively accessible to qualified generic manufacturers. Extended-release and injectable products require more technical capability. These barriers can protect a supplier’s margin temporarily, but they do not amount to durable molecule-level exclusivity.

Key Takeaways

• DIAMOX is the legacy brand of acetazolamide, a mature carbonic anhydrase inhibitor.
• The U.S. market is dominated by generic acetazolamide.
• Original composition, therapeutic-use, and brand exclusivity have expired.
• No current DIAMOX patent estate appears capable of supporting meaningful market exclusivity.
• Paragraph IV litigation is less important than manufacturing, supply, and regulatory execution.
• Immediate-release tablets are highly commoditized.
• Extended-release and injectable products offer greater operational differentiation but higher development and manufacturing risk.
• Standalone DIAMOX revenue is generally not publicly disclosed.
• The financial profile is stable unit demand, low pricing, and occasional shortage-driven volatility.
• The principal investment risk is supply disruption and margin compression, not generic patent entry.

FAQs

Is acetazolamide the same drug as DIAMOX?

Yes. DIAMOX is a brand name for acetazolamide. Generic acetazolamide products contain the same active ingredient, subject to FDA approval for the relevant dosage form and strength.

Does DIAMOX have orphan-drug exclusivity?

No current orphan-drug exclusivity is generally associated with the legacy DIAMOX product. Its principal indications and commercial history predate the modern orphan-drug market structure.

Can a generic manufacturer obtain market exclusivity for acetazolamide?

A manufacturer generally cannot obtain molecule-level exclusivity for an old generic drug. Limited exclusivity could arise from a qualifying new formulation, new indication, or regulatory pathway, but such rights would be product-specific and time-limited.

Is DIAMOX a high-growth pharmaceutical asset?

No. DIAMOX is a mature, low-growth pharmaceutical asset. Its commercial value depends on recurring demand, supply reliability, and portfolio economics rather than sales expansion or patent protection.

What would increase the value of an acetazolamide supplier?

The strongest value drivers would be approved products in supply-constrained presentations, reliable manufacturing, hospital contracts, multiple dosage forms, and the ability to maintain supply during competitor shortages.

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. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugsatfda
3. U.S. Food and Drug Administration. (n.d.). Drug shortages. https://www.fda.gov/drugs/drug-safety-and-availability/drug-shortages
4. American Society of Health-System Pharmacists. (n.d.). ASHP drug shortages resource center. https://www.ashp.org/drug-shortages
5. U.S. Food and Drug Administration. (n.d.). DailyMed and FDA-approved labeling for acetazolamide products. https://dailymed.nlm.nih.gov/dailymed/