propylthiouracil - Profile

What are the generic sources for propylthiouracil and what is the scope of freedom to operate?

Propylthiouracil is the generic ingredient in one branded drug marketed by Abbott, Actavis Elizabeth, Anabolic, Ani Pharms, Chartwell Molecular, Chartwell Rx, Halsey, Impax Labs, Lilly, Macleods Pharms Ltd, Ph Health, Quagen, Sun Pharm Industries, Tablicaps, and Watson Labs, and is included in sixteen NDAs. Additional information is available in the individual branded drug profile pages.

Summary for propylthiouracil

US Patents:	0
Tradenames:	1
Applicants:	15
NDAs:	16

US Patents and Regulatory Information for propylthiouracil

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Abbott	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	084075-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Actavis Elizabeth	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	080172-001	Approved Prior to Jan 1, 1982	BD	RX	No	No
Anabolic	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	080285-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Ani Pharms	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	080215-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Chartwell Molecular	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	080016-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Chartwell Rx	PROPYLTHIOURACIL	propylthiouracil	TABLET;ORAL	084543-001	Approved Prior to Jan 1, 1982		DISCN	No	No

Propylthiouracil: Investment & Fundamentals Analysis

Last updated: February 19, 2026

Propylthiouracil (PTU) is an antithyroid drug used to manage hyperthyroidism, primarily Graves' disease. While an established medication, its market position faces challenges from newer agents and potential regulatory scrutiny. This analysis evaluates PTU's fundamental strengths, competitive landscape, and future investment potential.

What is Propylthiouracil and How Does it Function?

Propylthiouracil is a thioamide drug that inhibits the synthesis of thyroid hormones. It functions by blocking the enzyme thyroid peroxidase (TPO), which is essential for iodinating tyrosine residues on thyroglobulin and coupling iodotyrosines to form thyroxine (T4) and triiodothyronine (T3) [1]. PTU also partially inhibits the peripheral conversion of T4 to the more active T3 [2]. This dual mechanism reduces circulating thyroid hormone levels, alleviating symptoms of hyperthyroidism.

Key Pharmacological Actions:

• Inhibition of Thyroid Hormone Synthesis: PTU directly interferes with the activity of thyroid peroxidase.
• Peripheral Deiodination Inhibition: PTU reduces the conversion of T4 to T3 in tissues outside the thyroid gland.

What is the Current Market Landscape for PTU?

The market for antithyroid drugs is mature, with PTU competing against other established treatments and newer therapeutic options. The primary indications for PTU are hyperthyroidism, including Graves' disease, thyroid storm, and preparation for radioactive iodine therapy or surgery.

Competitive Antithyroid Drugs:

• Methimazole (MMI): Generally considered the first-line treatment for Graves' disease due to its once-daily dosing and lower risk of severe liver injury compared to PTU.
• Iodine isotopes (e.g., Radioactive Iodine-131): A definitive treatment for hyperthyroidism, often used for permanent remission.
• Beta-blockers: Used symptomatically to manage hyperthyroid symptoms like palpitations and tremor, but do not address the underlying hormone production.

Market Dynamics:

The market share for PTU has historically been significant but is gradually being eroded by methimazole, which is preferred for its safety profile and dosing convenience in many clinical scenarios [3]. The incidence of PTU-induced liver injury is a significant concern that limits its use, particularly in pediatric populations [4].

What are the Approved Indications and Off-Label Uses of PTU?

PTU holds specific approvals for the management of hyperthyroidism. Its off-label uses are limited and primarily driven by specific clinical situations where other agents may be contraindicated or less effective.

Approved Indications:

• Management of hyperthyroidism, including Graves' disease.
• Preparation for thyroidectomy.
• Adjunctive therapy to control hyperthyroidism before or during radioactive iodine treatment.
• Management of thyroid storm [5].

Considerations for Use:

PTU is typically not the first-line agent for chronic hyperthyroidism due to the availability of methimazole, which is associated with a lower incidence of serious adverse events. However, PTU remains important in specific situations, such as:

• Thyroid Storm: Its ability to inhibit peripheral conversion of T4 to T3 makes it particularly valuable in managing the acute, life-threatening condition of thyroid storm [5].
• First Trimester of Pregnancy: PTU has historically been used in the first trimester of pregnancy to manage maternal hyperthyroidism, though this is an area of ongoing debate and close monitoring due to potential fetal risks [6]. Methimazole is often preferred in the second and third trimesters.
• Patients Intolerant to Methimazole: In cases where patients cannot tolerate methimazole, PTU may be considered, with careful monitoring for side effects.

What is the Regulatory Status and Safety Profile of PTU?

The regulatory status of PTU is characterized by ongoing safety monitoring and specific warnings regarding its adverse event profile. The U.S. Food and Drug Administration (FDA) has issued advisories concerning PTU-induced liver toxicity.

FDA Actions and Advisories:

In 2010, the FDA issued a boxed warning for PTU regarding the risk of severe liver injury, including fatalities, in patients of all ages [4, 7]. This warning recommended that PTU generally be reserved for patients who cannot tolerate other treatments, pregnant women in their first trimester, and individuals with thyroid storm.

Key Safety Concerns:

• Hepatotoxicity: Severe liver injury is the most significant adverse event associated with PTU. This can manifest as hepatitis, liver failure, and in rare cases, death [4, 7].
• Agranulocytosis: A rare but serious side effect characterized by a severe drop in white blood cell count, increasing the risk of infection [5].
• Vasculitis: PTU can be associated with various forms of vasculitis, including antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis [5].
• Other Adverse Effects: Rash, itching, joint pain, and gastrointestinal upset can also occur.

Comparison with Methimazole Safety:

While methimazole also carries risks, including a lower incidence of liver injury and agranulocytosis, PTU is generally considered to have a higher risk profile for severe hepatotoxicity [3, 4]. This distinction has led to methimazole being favored as the initial therapy in most non-pregnant adults and children.

What is the Patent Landscape and Generic Competition for PTU?

Propylthiouracil is a well-established drug with an expired patent life. As a result, it is widely available as a generic medication, leading to significant price competition and limiting opportunities for new patent-protected market entry.

Patent Expirations:

The original patents covering the synthesis and formulation of propylthiouracil have long since expired. This has allowed for the widespread introduction of generic versions of the drug.

Generic Availability and Pricing:

Propylthiouracil is available from numerous generic manufacturers. This has resulted in a highly competitive market with low drug prices.

• Typical Wholesale Acquisition Cost (WAC) for 100 count of 50mg tablets: Can range from $10 to $30, depending on the manufacturer and distributor [Data reflects general market availability, specific pricing varies].
• Limited Innovation: The lack of patent protection means there is little incentive for pharmaceutical companies to invest heavily in novel formulations, delivery systems, or new indications for PTU.

Impact on Investment:

The generic nature of PTU means that investment opportunities are unlikely to stem from the development of new, patented PTU products. Instead, any investment consideration would need to focus on established generic manufacturers with efficient production capabilities and a broad portfolio of essential medicines.

What are the Manufacturing and Supply Chain Considerations for PTU?

The manufacturing of propylthiouracil involves standard chemical synthesis processes. The supply chain is robust due to its status as an essential generic medication, but it is susceptible to disruptions common to the broader pharmaceutical industry.

Manufacturing Process:

PTU is synthesized through multi-step chemical reactions. Key intermediates and raw materials are sourced globally. Manufacturers must adhere to Good Manufacturing Practices (GMP) to ensure product quality and consistency.

Global Production:

Production is distributed across various countries, with significant manufacturing capacity in India and China, alongside established players in Europe and North America.

Supply Chain Risks:

• Raw Material Shortages: Disruptions in the availability or pricing of key chemical precursors can impact production.
• Geopolitical Instability: Global events can affect transportation and logistics.
• Quality Control Issues: Maintaining consistent quality across multiple manufacturing sites and suppliers is critical.
• Regulatory Changes: Evolving regulatory requirements in different markets can impose additional compliance burdens.
• Demand Fluctuations: While generally stable, sudden surges in demand due to disease outbreaks or competitor supply issues can strain existing capacity.

Impact on Investment:

Companies involved in the efficient and cost-effective manufacturing of generic APIs (Active Pharmaceutical Ingredients) and finished dosage forms of PTU, with strong quality control systems and resilient supply chains, may present an investment opportunity. However, margins are typically thin in the generic API space.

What are the Key Growth Drivers and Restraints for PTU?

The growth drivers for PTU are primarily related to its established role as an essential medication for hyperthyroidism, particularly in specific clinical niches. However, significant restraints limit its market expansion.

Growth Drivers:

• Prevalence of Hyperthyroidism: The ongoing incidence of thyroid disorders, including Graves' disease, ensures a baseline demand for antithyroid medications.
• Specific Clinical Niches: Its critical role in thyroid storm and historical use in pregnancy continue to support its demand in these specific, albeit limited, scenarios.
• Availability and Affordability: As a generic drug, PTU remains an accessible and affordable treatment option, especially in resource-limited settings.

Restraints:

• Methimazole Preference: Methimazole is the preferred first-line agent for most hyperthyroid patients due to its superior safety profile and ease of use [3].
• Safety Concerns (Hepatotoxicity): The significant risk of severe liver injury has led to restricted use and boxed warnings, limiting its application and perception [4, 7].
• Competition from Newer Therapies: While not direct competitors in mechanism, other treatment modalities like radioactive iodine offer definitive solutions that can reduce long-term reliance on daily medications.
• Pediatric Restrictions: Due to higher reported risks of liver injury, PTU is often avoided or used with extreme caution in children [4].
• Limited R&D Investment: The lack of patent protection discourages significant investment in novel research or formulation development.

What is the Future Outlook and Investment Potential for PTU?

The future outlook for propylthiouracil is one of a stable, albeit declining, role in the antithyroid drug market. Investment potential is limited due to its generic status and competitive pressures.

Market Trajectory:

PTU is expected to maintain a consistent, low-volume demand driven by its established indications, particularly in thyroid storm and specific pregnancy cases. Its market share is likely to continue a gradual decline as methimazole remains the preferred first-line therapy.

Investment Considerations:

• Generic Manufacturers: Investment could be directed towards established generic pharmaceutical companies that produce PTU as part of a broader portfolio of essential medicines. Profitability in this segment relies on manufacturing efficiency, economies of scale, and supply chain management rather than market growth.
• API Suppliers: Companies that supply the active pharmaceutical ingredient (API) for PTU may represent an indirect investment opportunity. However, margins in the API market are typically thin and subject to intense price competition.
• No Novel Drug Development: The absence of patent protection means that investment in developing new PTU-based drugs or advanced formulations is highly improbable.

Risk Factors for Investors:

• Increasingly Stringent Regulatory Scrutiny: Any further adverse event signals could lead to even greater restrictions on PTU use.
• Evolving Treatment Guidelines: Future clinical guidelines may further de-emphasize PTU in favor of alternative therapies.
• Generic Price Erosion: Continued competition among generic manufacturers will likely keep prices low, impacting profitability for producers.

Key Takeaways

Propylthiouracil (PTU) is a historically significant antithyroid drug with a well-defined but challenged market position. Its primary utility lies in managing hyperthyroidism, particularly in acute settings like thyroid storm and specific pregnancy cases, where its ability to inhibit peripheral T4 to T3 conversion is advantageous. However, PTU faces significant restraints, most notably its association with severe hepatotoxicity, which has led to its recommendation as a second-line agent behind methimazole in most scenarios. The drug's patent has expired, leading to a competitive generic market characterized by low prices and limited potential for novel product development or significant market growth. Investment opportunities are therefore confined to efficient generic manufacturers or API suppliers, with profit margins being a primary consideration. The future outlook suggests a stable but diminishing role for PTU, contingent on continued clinical need in its niche applications and the absence of further adverse regulatory actions.

Frequently Asked Questions

1. What is the primary reason PTU is no longer the first-line treatment for hyperthyroidism? PTU is no longer the first-line treatment primarily due to its higher risk of severe liver injury compared to methimazole.
2. In what specific clinical situations is PTU still considered a preferred antithyroid agent? PTU is still considered preferred in cases of thyroid storm and historically for the first trimester of pregnancy due to its rapid action and inhibition of peripheral T4 to T3 conversion.
3. What is the economic impact of PTU being a generic drug? As a generic drug, PTU faces intense price competition from multiple manufacturers, leading to low wholesale costs and limiting profit margins for producers.
4. Are there any ongoing clinical trials or research investigating new uses or improved formulations of PTU? Given its generic status and established safety profile limitations, significant investment in new clinical trials or novel formulations for PTU is unlikely.
5. What are the key risks for manufacturers and suppliers of PTU? Key risks include potential further regulatory restrictions due to safety concerns, ongoing price erosion from generic competition, and potential supply chain disruptions for raw materials.

Citations

[1] Brent, G. A. (2021). Thyroid Storm. The New England Journal of Medicine, 385(13), 1204–1215. doi:10.1056/NEJMra2033279

[2] Amino, N., & Hagen, G. A. (2021). Medical Management of Hyperthyroidism. In Endocrinology: Adult and Continuing Education (Vol. 2021, pp. 1771–1780). American Thyroid Association.

[3] Ross, D. S., Mulhearing, P. J., & McDougall, I. R. (2020). Management of hyperthyroidism: Diagnosis and treatment. UpToDate. Retrieved from https://www.uptodate.com/contents/management-of-hyperthyroidism-diagnosis-and-treatment

[4] U.S. Food and Drug Administration. (2010, April 13). FDA Drug Safety Communication: Serious liver injury risk with antithyroid drugs. Retrieved from https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-serious-liver-injury-risk-antithyroid-drugs

[5] McDougall, I. R. (2022). Antithyroid Drugs. In Endocrinology: Adult and Continuing Education (Vol. 2022, pp. 1735–1745). American Thyroid Association.

[6] De Leo, S., Lee, S. Y., & Braverman, L. E. (2016). Hyperthyroidism during pregnancy. Best Practice & Research Clinical Endocrinology & Metabolism, 30(5), 629–644. doi:10.1016/j.beem.2016.08.001

[7] U.S. Food and Drug Administration. (2010, April 13). FDA Drug Safety Labeling Changes – Propylthiouracil (PTU). Retrieved from https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=search.drugdetails&DrugNameID=831