CLINICAL TRIALS PROFILE FOR PHENYTOIN

505(b)(2) Clinical Trials for phenytoin

This table shows clinical trials for potential 505(b)(2) applications. See the next table for all clinical trials

Trial Type	Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
OTC	NCT00011063 ↗	Effect of Ginkgo Biloba on Phenytoin Elimination	Completed	National Institutes of Health Clinical Center (CC)	Phase 1	2001-02-01	This study will examine how the herbal remedy ginkgo biloba may affect the body's elimination of other medicines. Many people take ginkgo biloba to improve memory, mental alertness and overall feeling of well being. Since this product is considered a food supplement and not a drug, it is not subject to the rigorous pre-market testing required for prescription and over-the-counter (OTC) drugs. As a result, information has not been collected on possible interactions between ginkgo biloba and other medications. This study will look at how ginkgo biloba affects the elimination of phenytoin-a medication used to treat patients with seizures. Normal healthy volunteers 21 years of age or older may be eligible for this 40-day study. Candidates will provide a medical history and undergo a physical examination and routine blood tests. Women of childbearing age must use a reliable form of birth control other than oral contraceptives ("the pill"). For at least 2 weeks before the study and throughout its duration, study participants may not have any of the following: 1) medications that can affect platelet function (e.g., aspirin, Motrin, Advil, Nuprin, ibuprofen, etc.); 2) alcoholic beverages; 3) grapefruit and grapefruit juice; and 4) all medications except those given by study personnel. On day 1 of the study, subjects take one 500-mg dose of phenytoin at 8:00 A.M.. On an empty stomach. (Subjects fast the night before taking the phenytoin and are allowed to eat breakfast 2 hours after the dose). Blood samples are drawn just before dosing and again at 0.5, 1, 1.5, 2, 4, 6, 8, 10, 12, 24, 32, 48, 72 and 96 hours after the dose. Blood drawn on this first study day is collected through a catheter (small plastic tube) placed in a vein to avoid multiple needlesticks. After the 12-hour sample is collected, the subject goes home and then returns to the clinic for the remaining blood draws, which are taken by direct needlestick. When the blood sampling is completed, subjects begin ginkgo therapy. The NIH Clinical Center provides participants a supply of 60-mg capsules of ginkgo to take twice a day (at 8 A.M. and 8 P.M..) for 4 weeks. At the end of the 4 weeks, subjects are given a second dose of phenytoin as described above and repeat the blood sampling procedure. Subjects continue taking ginkgo during this second phenytoin study.

All Clinical Trials for phenytoin

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00000285 ↗	Effects of Phenytoin on Cocaine Use in Humans - 2	Completed	University of Minnesota	Phase 1	1996-05-01	The purpose of this study is to determine the effects of phenytoin on the self-administration of smoked cocaine.
NCT00000285 ↗	Effects of Phenytoin on Cocaine Use in Humans - 2	Completed	University of Minnesota - Clinical and Translational Science Institute	Phase 1	1996-05-01	The purpose of this study is to determine the effects of phenytoin on the self-administration of smoked cocaine.
NCT00000285 ↗	Effects of Phenytoin on Cocaine Use in Humans - 2	Completed	National Institute on Drug Abuse (NIDA)	Phase 1	1996-05-01	The purpose of this study is to determine the effects of phenytoin on the self-administration of smoked cocaine.
NCT00004403 ↗	Randomized Study of Albendazole in Patients With Epilepsy Due to Neurocysticercosis	Completed	Johns Hopkins University	N/A	2000-05-01	OBJECTIVES: I. Determine the effect of antiparasitic treatment with albendazole on the severity and duration of epilepsy due to neurocysticercosis. II. Determine the effect of a short course of albendazole on Taenia solium cysts present in the brain. III. Determine the natural regression of cerebral T. solium cysts in patients given placebo and their response to treatment at the end of the study.

Clinical Trial Conditions for phenytoin

Condition Name

Condition Name for phenytoin
Intervention	Trials
Epilepsy	23
Healthy	13
Seizures	8
Epilepsies, Partial	5

Condition MeSH

Condition MeSH for phenytoin
Intervention	Trials
Epilepsy	26
Seizures	16
Status Epilepticus	12
Epilepsies, Partial	6

Clinical Trial Locations for phenytoin

Trials by Country

Trials by Country for phenytoin
Location	Trials
United States	138
India	8
Egypt	7
Israel	6
Spain	6

Trials by US State

Trials by US State for phenytoin
Location	Trials
New York	11
Texas	10
Maryland	10
California	8
Arizona	7

Clinical Trial Progress for phenytoin

Clinical Trial Phase

Clinical Trial Phase for phenytoin
Clinical Trial Phase	Trials
PHASE4	5
PHASE3	1
PHASE2	5

Clinical Trial Status

Clinical Trial Status for phenytoin
Clinical Trial Phase	Trials
Completed	73
Recruiting	19
Terminated	17

Clinical Trial Sponsors for phenytoin

Sponsor Name

Sponsor Name for phenytoin
Sponsor	Trials
National Cancer Institute (NCI)	6
Johnson & Johnson Pharmaceutical Research & Development, L.L.C.	6
Emory University	5

Sponsor Type

Sponsor Type for phenytoin
Sponsor	Trials
Other	195
Industry	53
NIH	14

Clinical Trials Update, Market Analysis, and Projection for Phenytoin

Last updated: October 28, 2025

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Introduction

Phenytoin, a well-established anticonvulsant drug primarily used for seizure management, remains a pivotal asset in neurology. Since its approval in 1953, it has played a foundational role in epilepsy treatment. However, evolving clinical insights, emerging formulations, and increasing focus on personalized medicine necessitate continuous updates regarding its clinical trials activity, market dynamics, and future projections.

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Current Status of Clinical Trials

Ongoing Clinical Trials and Recent Initiatives

While phenytoin is a longstanding pharmaceutical, recent clinical trial efforts focus primarily on optimizing its delivery methods, reducing adverse effects, and expanding indications:

• Formulation Enhancements: Several trials are exploring aqueous and nano-formulations to improve bioavailability and reduce side effects. For instance, a recent study (NCT04578945) investigates a liposomal phenytoin formulation for intravenous use, aiming to provide rapid seizure control with minimized toxicity.

• Phenytoin in Neurological Disorders: Investigations are underway assessing its efficacy in non-epileptic neurological conditions. A notable trial (NCT04632130) studies phenytoin's neuroprotective potential in traumatic brain injury, reflecting its broader therapeutic exploration.

• Pharmacogenomics and Personalized Dosing: Trials are exploring genetic markers influencing phenytoin metabolism (e.g., CYP2C9 variants), aiming to optimize dosing, minimize adverse effects, and enhance therapeutic outcomes.

Regulatory and Investment Trends

Phenytoin's patent expiry and generic availability have limited direct pharmaceutical development. Nonetheless, regulatory agencies like the FDA and EMA continue to monitor its safety profile, with some updates to prescribing information reflecting new understanding of adverse effects, notably dermatologic reactions and hypersensitivity syndromes.

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Market Analysis

Current Market Landscape

Phenytoin remains a widely prescribed antiepileptic drug globally, with an estimated market size valued at approximately $450 million USD in 2022 (Statista). Its usage persists in both developed and emerging markets, largely driven by its affordability and proven efficacy.

• Regional Dynamics: North America commands the largest share, attributed to established healthcare infrastructure and high prevalence of epilepsy. The Asia-Pacific region shows rapid growth, driven by increasing awareness and expanding healthcare access. Europe maintains stable demand with a shift towards newer agents but still relies heavily on generics like phenytoin.

• Market Segments: The market is predominantly composed of oral formulations (tablet, suspension). Injectable formulations, although less commonly used, are crucial in acute settings and intensive care units.

Competitive Landscape

The market is characterized by a dominance of generic manufacturers such as Teva Pharmaceuticals, Mylan, and Sandoz. Limited proprietary formulations are available; the main differentiation lies in excipient quality, manufacturing standards, and pricing strategies. No new patentable phenytoin formulations have emerged since the mid-2000s, impacting innovation dynamics.

Market Challenges

• Toxicity and Side Effects: Known adverse effects, including gingival hyperplasia, rash, and hepatotoxicity, influence prescribing patterns and patient adherence.

• Drug Interactions: Phenytoin’s enzyme-inducing properties complicate polypharmacy management.

• Emergence of Newer Antiepileptics: Advances with drugs like levetiracetam and lamotrigine have led to reduced market share for phenytoin in certain markets.

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Future Market Projections

Growth Drivers

• Rising Epilepsy Prevalence: Global estimates report approximately 50 million people with epilepsy (WHO), ensuring continuous demand.

• Developing Markets: Increased healthcare investments and pharmacoeconomic factors favor the use of affordable drugs like phenytoin.

• Formulation Innovations: Efforts to develop safer, more tolerable formulations could reignite interest, especially in acute and special-population contexts.

Market Forecast (2023-2030)

Based on current trends and assumptions of slow but steady growth, the phenytoin market is projected to grow at a CAGR of 2-3%. By 2030, the global market valuation is expected to reach $530-$550 million USD.

Potential Disruptors

• Regulatory Changes: Stricter safety standards may impact formulations, especially generics.

• Technological Advancements: Breakthroughs in personalized therapies could diminish reliance on traditional drugs like phenytoin.

• Development of Novel Antiepileptics: Successes in gene therapy and neurostimulation could reshape epilepsy management paradigms.

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Implications for Industry Stakeholders

• Pharmaceutical Companies: Focus on bioavailability improvements and safety profiles can rejuvenate existing formulations.

• Investors: Moderate growth outlook suggests cautious investment, with opportunities in adjunct formula development and niche indications.

• Clinicians and Researchers: Ongoing research into pharmacogenetics and targeted delivery may redefine phenytoin’s role, especially in personalized medicine.

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Key Takeaways

• Stable yet mature market: Phenytoin continues to be a cornerstone in epilepsy management; however, innovation is limited predominantly to formulation research.

• Clinical trials momentum: Trials mainly explore alternative formulations, wider neurological applications, and pharmacogenomics, indicating incremental optimization rather than paradigm shifts.

• Market outlook: Modest growth driven by existing demand and demographic trends, with potential for expansion in emerging markets and niche applications.

• Challenges to growth: Safety concerns and competition from newer agents may restrict aggressive market expansion.

• Opportunities: Development of safer formulations and personalized therapy approaches can extend the drug's lifecycle and market relevance.

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FAQs

1. What are the latest clinical trial developments involving phenytoin?
   Recent trials focus on novel formulations such as liposomal and nano-based delivery systems, aiming to reduce side effects and improve pharmacokinetics, alongside exploring new therapeutic indications like traumatic brain injury.

2. How does the global market for phenytoin look today?
   Valued at approximately $450 million in 2022, the market remains sizeable primarily because of its affordability and proven efficacy, with growth driven by developing regions and incremental formulation improvements.

3. What factors could influence the future demand for phenytoin?
   Factors include the prevalence of epilepsy, regulatory changes regarding safety, competition from newer antiepileptic drugs, and innovations enabling targeted therapy.

4. Are there any significant patent or regulatory hurdles impacting phenytoin development?
   Since its patent expired decades ago, the primary hurdles relate to safety concerns and regulatory standards for generics, but no substantial patent-related development bottlenecks currently exist.

5. What opportunities exist for new entrants in the phenytoin market?
   Opportunities lie in developing safer, more tolerable formulations, expanding indications through clinical trials, and leveraging pharmacogenomic insights for personalized dosing.

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References

[1] WHO. Epilepsy Fact Sheet. World Health Organization, 2022.
[2] Statista. Antiepileptic Drug Market Revenue Worldwide. 2022.
[3] ClinicalTrials.gov. Phenytoin-related trials. Accessed 2023.
[4] FDA Drug Database. Approved formulations and safety updates on phenytoin. 2022.