TRIOSTAT Drug Patent Profile

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

Triostat is a drug marketed by Ph Health and is included in one NDA.

The generic ingredient in TRIOSTAT is liothyronine sodium. There is one drug master file entry for this compound. Nineteen suppliers are listed for this compound. Additional details are available on the liothyronine sodium profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Triostat

A generic version of TRIOSTAT was approved as liothyronine sodium by XGEN PHARMS on August 17^th, 2005.

Summary for TRIOSTAT

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	76
Clinical Trials:	2
Patent Applications:	1,502
Drug Prices:	Drug price information for TRIOSTAT
What excipients (inactive ingredients) are in TRIOSTAT?	TRIOSTAT excipients list
DailyMed Link:	TRIOSTAT at DailyMed

See drug prices for TRIOSTAT

Recent Clinical Trials for TRIOSTAT

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

Sponsor	Phase
Seattle Children's Hospital	Phase 3
Michael Portman	Phase 3

See all TRIOSTAT clinical trials

US Patents and Regulatory Information for TRIOSTAT

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Ph Health	TRIOSTAT	liothyronine sodium	INJECTABLE;INJECTION	020105-001	Dec 31, 1991		DISCN	Yes	No

Triostat Market Dynamics, FDA Status, Patent Exposure, and Financial Trajectory

Last updated: September 26, 2026

Triostat is an injectable liothyronine sodium product used primarily for myxedema coma, severe hypothyroidism, and thyroid-hormone suppression testing. Its commercial market is small, hospital-centered, and highly sensitive to supply interruptions. The product has little remaining patent value, no meaningful regulatory exclusivity, and limited disclosed financial exposure for its current or former branded manufacturer. The principal commercial issue is availability rather than premium pricing or market expansion.

What is Triostat and how is it used?

Triostat is the brand name for liothyronine sodium injection, a synthetic form of triiodothyronine, or T3. The product is administered intravenously and is used when rapid thyroid-hormone replacement is clinically necessary.

Attribute	Triostat
Active ingredient	Liothyronine sodium
Dosage form	Injectable solution
Common strength	10 mcg/mL
Administration	Intravenous, with other routes described in labeling
Primary use	Myxedema coma or precoma
Other use	Thyroid suppression testing
Drug class	Thyroid hormone
FDA pathway	New Drug Application product
Commercial channel	Hospitals, acute-care facilities, specialty wholesalers
Biosimilar relevance	None

The FDA label identifies myxedema coma as the principal emergency indication and emphasizes cautious dosing because excessive thyroid hormone can cause cardiovascular complications (U.S. Food and Drug Administration [FDA], n.d.-a).

Triostat differs commercially from oral liothyronine products such as Cytomel. Oral products serve chronic outpatient treatment, while Triostat is used mainly in acute-care settings. The injectable product therefore has a much smaller patient base and a more concentrated purchasing channel.

What is the FDA status of Triostat?

Triostat has historically been marketed under an FDA-approved NDA. Pfizer became associated with the product following its acquisition of King Pharmaceuticals, which had marketed several specialty and hospital products. Public drug databases have also listed liothyronine sodium injection products under generic marketing authorizations.

The key regulatory points are:

Regulatory issue	Assessment
FDA approval	Established prescription product
Approved indication	Myxedema coma/precoma and thyroid suppression testing
Controlled substance status	Not controlled
REMS requirement	No established product-specific REMS
Pediatric exclusivity	Not relevant to the current commercial position
Orphan-drug exclusivity	No current market significance identified
New chemical entity exclusivity	Expired decades ago
Current commercial status	Subject to product-listing and supply-status changes
Orange Book value	No material active patent exclusivity expected

FDA product listings can change when a company discontinues a product, transfers a product, or updates its marketing status. A discontinued listing does not necessarily mean that the active ingredient is unavailable. Generic liothyronine sodium injection may remain available even if the Triostat brand is no longer actively promoted or distributed.

When does Triostat lose exclusivity?

Triostat has no commercially meaningful remaining molecule or formulation exclusivity.

Liothyronine sodium is an old thyroid hormone. Its active-ingredient exclusivity expired long before the modern generic-drug market developed. Any original Triostat patent rights would have expired decades ago. A new patent covering the legacy active ingredient would not be available merely because the product remains clinically useful.

The relevant protection profile is therefore:

Protection type	Current significance
Active-ingredient patent	Expired
Original product patent	Expired or no longer commercially relevant
Formulation patent	No material active protection identified
Method-of-use patent	No material active protection identified for the established indications
Pediatric exclusivity	None of practical relevance
Orphan exclusivity	None of practical relevance
Data exclusivity	Expired
Patent-based generic barrier	Low

Triostat is consequently exposed to generic substitution and hospital purchasing pressure. Its commercial position depends on manufacturing capacity, FDA compliance, distribution, and supply reliability.

What patents protect Triostat?

No strong, currently relevant patent estate is associated with the legacy Triostat product.

The commercial protection formerly associated with Triostat would have come from the original NDA, trademark rights, manufacturing know-how, and distribution relationships. Trademark protection can preserve the Triostat name, but it does not prevent competitors from selling liothyronine sodium injection under a generic name.

A generic manufacturer does not need to reproduce the Triostat brand. It generally needs to demonstrate pharmaceutical equivalence and bioequivalence or satisfy the applicable approval requirements for an injectable product. For an injectable thyroid hormone, manufacturing controls, sterility, potency, stability, container closure, and supply consistency are more important barriers than patent rights.

What formulations are protected by Triostat?

Triostat's injectable formulation has limited patent protection but meaningful technical requirements.

The relevant manufacturing risks include:

• Accurate microgram-level potency
• Sterility assurance
• Control of degradation products
• Stability throughout the labeled shelf life
• Compatibility with the container and closure system
• Validation of aseptic processing
• Reliable availability of active pharmaceutical ingredient
• Compliance with current good manufacturing practice requirements

These factors can restrict the number of reliable suppliers even when the product is legally open to generic competition. Injectable products are more difficult to manufacture than tablets because quality failures can create recalls, hospital shortages, and regulatory action.

The technical barrier is therefore operational rather than patent-based. A company can enter the market without infringing a meaningful Triostat patent, but it still needs an approved facility, qualified suppliers, validated processes, and a commercially viable distribution system.

How large is the Triostat market?

Triostat operates in a narrow emergency-care market. Demand is driven by the incidence of myxedema coma, hospital protocols, emergency department stocking decisions, and replacement of expiring inventory.

The market has several structural characteristics:

1. Low unit volume relative to oral thyroid drugs.
2. High clinical importance per unit.
3. Concentrated purchasing by hospitals and wholesalers.
4. Limited ability to substitute with oral products in critically ill patients.
5. Strong sensitivity to manufacturing interruptions.
6. Weak consumer-brand loyalty.
7. Limited opportunity for broad promotional growth.

Myxedema coma is rare compared with ordinary hypothyroidism. The emergency indication generates episodic demand, while thyroid suppression testing contributes a smaller and declining portion of usage as diagnostic practice changes.

The market can experience a mismatch between low annual demand and high service requirements. Manufacturers must maintain sterile production and inventory even though annual unit sales may not justify large-scale expansion. This dynamic makes the product vulnerable to discontinuation, backorders, and temporary shortages.

What is the financial trajectory for Triostat?

No standalone Triostat revenue series is generally disclosed in public filings. Pfizer and other large pharmaceutical companies report products within broader business segments, preventing reliable identification of Triostat-specific sales, margins, or market share.

The likely financial trajectory is:

Period	Commercial condition	Financial implication
Historical branded period	Protected by brand recognition and limited supplier competition	Higher pricing power than an open generic market
Generic-entry period	More suppliers and hospital substitution	Lower unit pricing and reduced brand share
Supply-constrained period	Shortages or limited manufacturing capacity	Temporary price increases and higher distributor value
Mature market	Low volume, low promotion, contract-driven purchasing	Limited revenue growth
Discontinuation or delisting period	Brand availability falls while generic demand remains	Revenue transfers to alternative suppliers

Triostat is unlikely to represent material revenue exposure for a diversified pharmaceutical company. Its strategic value is greater for a generic manufacturer with injectable capacity, a hospital-focused portfolio, or an established acute-care distribution network.

For hospitals, the financial issue is not the absolute cost of the drug. The larger exposure is the cost of delayed treatment, emergency procurement, protocol changes, and substitution management during shortages.

What is the Orange Book status of Triostat?

The Orange Book is relevant to Triostat primarily as a record of approved products and any listed patent or exclusivity claims. The product's commercial position does not appear to depend on an active patent term.

The practical Orange Book assessment is:

• No expected active composition-of-matter protection.
• No meaningful remaining regulatory exclusivity.
• No apparent patent barrier preventing approved generic competition.
• Any listed patents would need to be evaluated against their expiration, pediatric extensions, and product-specific scope.
• Product discontinuation status must be distinguished from withdrawal for safety or efficacy reasons.

A discontinued brand can still influence prescribing and procurement if hospitals retain the name in formularies. That commercial recognition does not create legal exclusivity.

Which companies are challenging Triostat?

The competitive threat is primarily generic substitution rather than a patent challenge.

Paragraph IV litigation is unlikely to be the central issue because the relevant active-ingredient and product patents are old or expired. Generic manufacturers can compete through ANDA approvals, contract supply, and hospital purchasing agreements rather than through high-value patent litigation.

Potential competitors include:

• FDA-approved generic liothyronine sodium injection suppliers
• Hospital-focused injectable manufacturers
• Contract manufacturers with sterile injectable capacity
• Wholesalers sourcing equivalent products during shortages
• Compounded pharmacies, where legally permissible and clinically appropriate

Compounded products are not equivalent to FDA-approved generics and do not provide the same regulatory assurance. Hospitals generally prefer approved products but may consider alternatives when supply is disrupted.

What patent litigation affects Triostat?

No major current patent litigation is central to Triostat's market position.

The product has no obvious litigation profile comparable to newer specialty drugs protected by formulation, method-of-use, or manufacturing patents. The main legal risks are more likely to involve:

• Product liability
• Manufacturing defects
• Labeling disputes
• Distribution contracts
• Shortage-related procurement issues
• Trademark ownership or brand-use rights
• FDA enforcement involving sterile manufacturing

Patent litigation would have limited economic value because the active ingredient is old, the indication is narrow, and generic competition is legally feasible.

What generic entry risks exist for Triostat?

Generic entry risk is high in legal terms but uneven in commercial terms.

A generic competitor can erode the Triostat brand through hospital substitution, formulary interchange, and lower contract pricing. Yet the small market may deter multiple entrants. This creates a market with low patent barriers but potentially limited dependable supply.

Generic entry is most likely to affect Triostat through:

• Reduced branded volume
• Lower average selling prices
• Hospital tender losses
• Wholesaler substitution
• Increased price transparency
• Reduced promotional investment
• Greater dependence on manufacturing reliability

The principal counterweight is supply scarcity. If only one or two suppliers remain active, a branded or legacy supplier may retain pricing leverage despite the absence of patent protection.

How does Triostat compare with Cytomel and generic liothyronine?

Product	Form	Primary market	Patent position	Commercial profile
Triostat	Injectable liothyronine	Hospital emergency care	No meaningful current exclusivity	Small, supply-sensitive
Cytomel	Oral liothyronine	Chronic outpatient treatment	Legacy product with generic competition	Larger outpatient presence
Generic liothyronine tablets	Oral	Chronic hypothyroidism and selected indications	Open generic market	Price-sensitive
Generic liothyronine injection	Injectable	Acute-care hospitals	Low patent barrier	Capacity- and shortage-sensitive
Levothyroxine products	Oral or injectable	Broad thyroid replacement market	Extensive generic competition	Much larger volume

Triostat cannot compete directly with most oral thyroid products in patients requiring rapid intravenous treatment. Conversely, its narrow hospital use limits its growth potential compared with levothyroxine and oral liothyronine.

What is the outlook for Triostat revenue and market share?

The base-case outlook is flat to declining branded revenue, with periodic volatility caused by supply conditions.

Revenue growth would require one of the following:

• A broader approved indication
• Expanded hospital adoption
• Persistent generic shortages
• A new commercial owner with stronger acute-care distribution
• A premium-priced presentation with operational advantages

None of these drivers is inherent in the legacy product. The more probable scenario is stable but low-volume demand, with revenue shifting among suppliers based on availability and contracting.

For investors and licensing teams, Triostat is better analyzed as a niche hospital product than as a growth pharmaceutical asset. Its value may lie in portfolio fit, sterile injectable infrastructure, and shortage resilience rather than in patent duration or market expansion.

Key Takeaways

• Triostat is injectable liothyronine sodium used mainly for myxedema coma and related acute-care indications.
• Its market is small, hospital-centered, and sensitive to supply interruptions.
• The active ingredient and original product rights have no meaningful remaining patent exclusivity.
• No material biosimilar issue applies because Triostat is a small-molecule drug, not a biologic.
• Generic competition is legally straightforward, but sterile injectable manufacturing limits dependable supply.
• Standalone Triostat revenue is not publicly reported by major manufacturers.
• The likely financial trajectory is low-volume, mature, and flat to declining for the branded product.
• The main commercial risks are discontinuation, shortages, hospital substitution, and contract-price erosion.
• The product has limited value as a standalone patent asset but may have strategic value within an acute-care injectable portfolio.

FAQs

Is Triostat still available in the United States?

Availability depends on current manufacturer listings, wholesaler inventory, and FDA supply status. Brand availability and availability of generic liothyronine sodium injection are separate questions.

Is Triostat interchangeable with Cytomel?

No. Triostat is an injectable product, while Cytomel is primarily an oral liothyronine product. Route, dosing, clinical use, and hospital protocols differ.

Can a generic manufacturer launch liothyronine injection without a Triostat license?

Yes, provided the manufacturer obtains the required FDA approval and meets applicable pharmaceutical, sterility, manufacturing, and labeling requirements. A Triostat trademark license is not required to sell an approved generic product.

Does Triostat qualify for orphan-drug protection?

The narrowness of myxedema coma does not by itself create orphan-drug exclusivity. Any orphan designation or exclusivity would require a separate FDA determination and would not be presumed from the product's small market.

Is Triostat an attractive licensing target?

It is generally more attractive to companies with sterile injectable manufacturing and hospital distribution than to companies seeking long-duration patent exclusivity. The opportunity is operational and supply-based, not primarily patent-based.

References

1. U.S. Food and Drug Administration. (n.d.-a). Triostat (liothyronine sodium) injection prescribing information. FDA.
2. U.S. Food and Drug Administration. (n.d.-b). Approved drug products with therapeutic equivalence evaluations. FDA.
3. U.S. Food and Drug Administration. (n.d.-c). Drug shortages. FDA.
4. Pfizer Inc. (2010). Pfizer completes acquisition of King Pharmaceuticals. Pfizer investor relations.
5. National Library of Medicine. (n.d.). DailyMed: Liothyronine sodium injection. U.S. National Library of Medicine.