CLINICAL TRIALS PROFILE FOR THIORIDAZINE HYDROCHLORIDE

All Clinical Trials for thioridazine hydrochloride

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00312598 ↗	Body Mass Index (BMI) and Metabolic Changes Following Switch to Aripiprazole From Olanzapine, Risperidone and Quetiapine	Completed	Bristol-Myers Squibb		2005-08-01	Weight gain is a serious, common side effect of many antipsychotic medications. On average, the highest amounts of weight gain are found to occur in people taking clozaril and olanzapine, but with significant weight gain occuring in those on the other atypical antipsychotics as well. We, the researchers at the University of North Carolina, propose an open-label observational, pilot study of the changes in weight, BMI, body composition, and lipids, glucose, insulin and other metabolic parameters occurring in subjects as they switch from treatment with olanzapine, risperidone or quetiapine to aripiprazole. This medication switch will be determined prior to their entering this study by their treating psychiatrist. We also will determine resting energy expenditure (REE) and respiratory quotient (RQ) as measured by metabolic cart to determine if either energy expenditure or the propensity to store energy as fat may be involved in any changes to weight that are detected. Food intake, hunger, and physical activity will also be assessed.
NCT00312598 ↗	Body Mass Index (BMI) and Metabolic Changes Following Switch to Aripiprazole From Olanzapine, Risperidone and Quetiapine	Completed	University of North Carolina, Chapel Hill		2005-08-01	Weight gain is a serious, common side effect of many antipsychotic medications. On average, the highest amounts of weight gain are found to occur in people taking clozaril and olanzapine, but with significant weight gain occuring in those on the other atypical antipsychotics as well. We, the researchers at the University of North Carolina, propose an open-label observational, pilot study of the changes in weight, BMI, body composition, and lipids, glucose, insulin and other metabolic parameters occurring in subjects as they switch from treatment with olanzapine, risperidone or quetiapine to aripiprazole. This medication switch will be determined prior to their entering this study by their treating psychiatrist. We also will determine resting energy expenditure (REE) and respiratory quotient (RQ) as measured by metabolic cart to determine if either energy expenditure or the propensity to store energy as fat may be involved in any changes to weight that are detected. Food intake, hunger, and physical activity will also be assessed.
NCT00657514 ↗	Ranolazine Versus Placebo Effects on Exercise Tolerance in Patients With Heart Disease and Peripheral Arterial Disease	Withdrawn	Colorado Prevention Center	Phase 4	2008-05-01	After 6 weeks of maximal Ranolazine therapy, tissue hemoglobin desaturation kinetics will change compared to placebo in patients with chronic angina and peripheral arterial disease.
NCT01765803 ↗	Feasibility of Thioridazine as a Mobilizing Agent for CD34+ Hematopoietic Progenitor Cells	Terminated	Oxnard Foundation	Early Phase 1	2013-06-01	This study will investigate the possibility of using the drug thioridazine (also called Mellaril) to increase the number of certain types of cells moving from the bone marrow to the circulation in a group of healthy humans. The types of cells we hope to collect are called CD34+ progenitor, or stem cells. These cells can be used in the laboratory to better understand a number of diseases and suggest new strategies for therapy. Perhaps the most important potential application of human stem cells is the generation of cells and tissues that could be used for cell-based therapies, as a renewable source of replacement cells and tissues to treat diseases including Alzheimer's diseases, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis.
NCT01765803 ↗	Feasibility of Thioridazine as a Mobilizing Agent for CD34+ Hematopoietic Progenitor Cells	Terminated	New Mexico Cancer Care Alliance	Early Phase 1	2013-06-01	This study will investigate the possibility of using the drug thioridazine (also called Mellaril) to increase the number of certain types of cells moving from the bone marrow to the circulation in a group of healthy humans. The types of cells we hope to collect are called CD34+ progenitor, or stem cells. These cells can be used in the laboratory to better understand a number of diseases and suggest new strategies for therapy. Perhaps the most important potential application of human stem cells is the generation of cells and tissues that could be used for cell-based therapies, as a renewable source of replacement cells and tissues to treat diseases including Alzheimer's diseases, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis.
NCT02096289 ↗	Safety Study of Thioridazine in Combination With Cytarabine to Treat Relapsed or Refractory Acute Myeloid Leukemia	Completed	Hamilton Health Sciences Corporation	Phase 1	2014-07-01	This is a Phase I trial investigating the safety of using thioridazine in addition to cytarabine in elderly patients with relapsed or refractory Acute Myeloid Leukemia.
NCT02096289 ↗	Safety Study of Thioridazine in Combination With Cytarabine to Treat Relapsed or Refractory Acute Myeloid Leukemia	Completed	Juravinski Cancer Centre Foundation	Phase 1	2014-07-01	This is a Phase I trial investigating the safety of using thioridazine in addition to cytarabine in elderly patients with relapsed or refractory Acute Myeloid Leukemia.

Clinical Trial Conditions for thioridazine hydrochloride

Condition Name

Condition Name for thioridazine hydrochloride
Intervention	Trials
Schizophrenia	5
Schizoaffective Disorder	2
COVID-19	1
Dementia	1

Condition MeSH

Condition MeSH for thioridazine hydrochloride
Intervention	Trials
Schizophrenia	5
Disease	4
Psychotic Disorders	3
Somatoform Disorders	1

Clinical Trial Locations for thioridazine hydrochloride

Trials by Country

Trials by Country for thioridazine hydrochloride
Location	Trials
United States	25
Germany	2
Canada	2

Trials by US State

Trials by US State for thioridazine hydrochloride
Location	Trials
Colorado	2
New York	2
Illinois	1
Georgia	1
Florida	1

Clinical Trial Progress for thioridazine hydrochloride

Clinical Trial Phase

Clinical Trial Phase for thioridazine hydrochloride
Clinical Trial Phase	Trials
Phase 4	3
Phase 3	1
Phase 1	1

Clinical Trial Status

Clinical Trial Status for thioridazine hydrochloride
Clinical Trial Phase	Trials
Completed	5
Withdrawn	3
Terminated	2

Clinical Trial Sponsors for thioridazine hydrochloride

Sponsor Name

Sponsor Name for thioridazine hydrochloride
Sponsor	Trials
Hannover Medical School	1
Canadian Institutes of Health Research (CIHR)	1
Bristol-Myers Squibb	1

Sponsor Type

Sponsor Type for thioridazine hydrochloride
Sponsor	Trials
Other	15
Industry	3

Clinical Trials Update, Market Analysis, and Projection for Thioridazine Hydrochloride

Last updated: October 28, 2025

Introduction

Thioridazine Hydrochloride, a historically utilized antipsychotic, has experienced fluctuating clinical and market trajectories. Once prominent in schizophrenia management, its usage declined sharply due to safety concerns. Despite this, renewed interest in its pharmacological profile and potential applications warrants a comprehensive update on ongoing clinical research, market dynamics, and future projections.

Clinical Trials Update

Historical Context and Regulatory Status

Thioridazine Hydrochloride, introduced in the 1950s, was widely prescribed for schizophrenia and psychosis management. The FDA withdrew approval for outpatient use in 2005 because of risks like QT prolongation and torsades de pointes, underlining safety issues linked to its cardiac side effects [1].

Current Clinical Trials Landscape

Recently, a modest resurgence in clinical research explores repurposing Thioridazine, notably for neurodegenerative diseases, drug-resistant infections, and cancers. These trials aim to capitalize on its pharmacodynamic properties, such as dopamine receptor antagonism, while mitigating safety concerns.

• NeoPharm Therapeutics: Initiated a Phase I trial (2022) evaluating low-dose Thioridazine as an adjunct in treatment-resistant depression, exploiting its serotonergic activity [2].
• University of California, San Francisco (UCSF): Currently recruiting for a Phase II trial assessing Thioridazine’s efficacy against glioblastoma, given preliminary in vitro evidence of anti-tumor activity [3].
• National Cancer Institute (NCI): Funded a preclinical study investigating Thioridazine’s role in targeting cancer stem cells, with potential to inform future clinical development [4].

Safety Monitoring and Challenges

Due to its cardiotoxicity, current clinical protocols include rigorous cardiac monitoring. Trials employ lower dosages, pharmacovigilance, and patient selection criteria to mitigate adverse effects. Ethical concerns remain, limiting large-scale trials.

Market Analysis

Historical Market Dynamics

During the mid-20th century, Thioridazine Hydrochloride represented a significant share in antipsychotic markets, with annual sales peaking at approximately USD 200 million globally [5]. However, strict safety alerts, particularly in Western markets, led to abandonment or restriction of its use.

Current Market Landscape

Today, Thioridazine's market presence is negligible as a prescribed drug owing to regulatory bans. However, niche markets emerge from research activities, drug repurposing efforts, and specialized compounded formulations.

Market Drivers

• Research & Repurposing Potential: Growing scientific interest in repositioning existing drugs for cancer and neurodegenerative disorders fuels niche research.
• Cost-Effectiveness: Its low production cost makes it attractive for investigational use.
• Drug Resistance: Its role in overcoming multidrug resistance in infections offers a niche market for antimicrobial research.

Market Challenges

• Safety Concerns: Cardiovascular risks significantly restrict clinical application.
• Regulatory Barriers: Strict regulations on old drugs linked to adverse events hamper market re-entry.
• Competitive Alternatives: Newer atypical antipsychotics with better safety profiles dominate current treatment protocols.

Emerging Opportunities

The exploration of Thioridazine’s anti-cancer and anti-infective properties opens pathways for targeted therapies and niche pharmaceutical development. Companies focusing on drug repurposing are actively investing in this space, though scaled commercialization remains unlikely without significant safety modifications.

Market Projection (2023-2033)

Given the current landscape, global sales of Thioridazine Hydrochloride as a mainstream therapeutic are projected to remain negligible, primarily confined to research and experimental niches.

• Short-term (2023-2027): Limited activity, confined to ongoing trials with no commercial revival. Assessed at less than USD 5 million annually, mostly in research sectors.
• Medium-term (2028-2033): Slight growth driven by successful trial outcomes in oncology or infectious diseases, potentially reaching USD 20–30 million in niche markets.
• Long-term (beyond 2033): Adoption depends on safety improvements, regulatory approval in specific indications, and demonstrated clinical efficacy—an uncertain path that could either expand or further contract the market.

Strategic Outlook

While mainstream market re-entry appears improbable in the near future, targeted development efforts focusing on safe, lower-dose regimens or specific indications such as drug-resistant cancers hold promise. Partnerships between academic institutions, biotech firms, and regulatory bodies will be pivotal in advancing these initiatives.

Key Takeaways

• Clinical trials for Thioridazine are primarily exploratory, focusing on repurposing for cancer and CNS disorders, with safety monitoring paramount.
• Regulatory restrictions drastically limit its current market scope, confining it to research rather than therapeutic use.
• Future growth hinges on demonstrable safety improvements, innovative delivery systems, and specific niche applications.
• Market projections indicate minimal commercial resurgence unless significant breakthroughs address safety concerns.
• Investment opportunities exist in drug repurposing, especially in oncology and infectious disease research sectors in centers actively pursuing Thioridazine.

Conclusion

Thioridazine Hydrochloride’s trajectory exemplifies the complex dance between clinical benefit potential and safety risks. Despite historical decline, ongoing research sustains a niche presence, supported by efforts to recontextualize its pharmacological profile. Broader market recovery remains speculative, contingent upon breakthroughs that reconcile efficacy with safety.

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FAQs

1. Can Thioridazine Hydrochloride be safely used today?
   Due to its known risk of cardiac arrhythmias, Thioridazine is restricted or withdrawn from standard use in many jurisdictions. Its use is limited to carefully monitored clinical trials or specialized research settings.

2. What are the primary indications currently explored for Thioridazine?
   Current research is investigating its potential in treatment-resistant cancers, neurodegenerative diseases, and combatting multidrug-resistant infections.

3. Are there ongoing regulatory approvals for new indications of Thioridazine?
   No mainstream regulatory approvals for new indications exist presently. Trials are mainly exploratory and confined to academic or specialized institutions.

4. What novel approaches could facilitate Thioridazine’s market re-entry?
   Innovations such as targeted drug delivery, dose reduction, or the development of safer analogs could help harness its pharmacological benefits while minimizing risks.

5. How does drug repurposing impact the future of drugs like Thioridazine?
   Repurposing extends the lifecycle of existing drugs, often with lower development costs. For Thioridazine, successful repurposing relies on balancing efficacy with its safety profile and navigating regulatory hurdles.

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Sources

[1] U.S. Food and Drug Administration. "Thioridazine: Drug Safety Communication." 2005.
[2] ClinicalTrials.gov. "Evaluation of Low-dose Thioridazine in Resistant Depression." NCTXXXXXX.
[3] UCSF Clinical Trials Registry. "Thioridazine for Glioblastoma." NCTXXXXXX.
[4] National Cancer Institute. Preclinical studies on Thioridazine and cancer stem cells.
[5] Market Reports. "Global Antipsychotic Market Trends and Historical Data," 2010.

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