CLINICAL TRIALS PROFILE FOR ACETYLCYSTEINE

505(b)(2) Clinical Trials for acetylcysteine

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	NCT01005810 ↗	A Trial of N-Acetylcysteine (an Over-the-Counter Medicine) in Adolescents Who Smoke Marijuana	Completed	National Institute on Drug Abuse (NIDA)	Phase 2	2009-09-01	This study is investigating how N-Acetylcysteine (NAC), an over-the-counter medication, will reduce marijuana use when combined with Contingency Management, a behavioral treatment. It is hypothesized that marijuana dependent adolescents who are treated with NAC will use less marijuana during treatment when compared to adolescents who receive a placebo.
OTC	NCT01005810 ↗	A Trial of N-Acetylcysteine (an Over-the-Counter Medicine) in Adolescents Who Smoke Marijuana	Completed	Medical University of South Carolina	Phase 2	2009-09-01	This study is investigating how N-Acetylcysteine (NAC), an over-the-counter medication, will reduce marijuana use when combined with Contingency Management, a behavioral treatment. It is hypothesized that marijuana dependent adolescents who are treated with NAC will use less marijuana during treatment when compared to adolescents who receive a placebo.
New Formulation	NCT01118663 ↗	Safety and Efficacy Study of a New Formulation of Acetylcysteine Injection	Terminated	Cumberland Pharmaceuticals	Phase 3	2010-09-01	The primary purpose of this study is determine if a new formulation of Acetadote is at least as effective as the current formulation in the prevention and treatment of acetaminophen overdose related liver injury.
OTC	NCT01241513 ↗	Induced Changes in Ventilatory Responsiveness and Altitude Exposure	Terminated	United States Army Research Institute of Environmental Medicine	Phase 4	2010-11-01	The main purpose of this study is to determine if a drug (acetyl-cysteine or ACCY) can increase the amount of oxygen in your body at a high altitude of 11,500 feet. ACCY is approved by the Food and Drug Administration (FDA) as a treatment or antidote for Tylenol overdoses. Other forms of ACCY are also sold over-the-counter as nutritional supplements. In this study, the FDA-approved form of ACCY will be used "off-label" (meaning in a way not approved by the FDA). This study is being conducted by researchers from the United States Army Research Institute of Environmental Medicine (USARIEM). The study will take place in the Altitude Chamber located in the basement of USARIEM. A total of approximately 30 volunteers (men and women, military and civilians) will take part in the study. They can expect to be in the study for a minimum of a few hours each day for two weeks. The investigators hypothesize that ACCY will improve ventilation and oxygenation while at altitude.
OTC	NCT03238300 ↗	Neuroscience-Informed Treatment Development for Adolescent Alcohol Use	Recruiting	National Institute on Alcohol Abuse and Alcoholism (NIAAA)	Phase 2	2017-10-16	This study will examine the effect of N-Acetylcysteine (NAC), an over-the-counter antioxidant supplement, on brains of youth (ages 15-19) using magnetic resonance imaging (MRI). 55 adolescents will receive, in a counterbalanced order, a 10-day course of NAC 1200 mg twice daily and a subsequent 10-day course of matched placebo twice daily, separated by 11 days. Urine and blood samples will be collected at baseline and urine samples again before and after each course of medication treatment. Participants will receive a 1- hour MRI scan at baseline and after each treatment trial.
OTC	NCT03238300 ↗	Neuroscience-Informed Treatment Development for Adolescent Alcohol Use	Recruiting	Medical University of South Carolina	Phase 2	2017-10-16	This study will examine the effect of N-Acetylcysteine (NAC), an over-the-counter antioxidant supplement, on brains of youth (ages 15-19) using magnetic resonance imaging (MRI). 55 adolescents will receive, in a counterbalanced order, a 10-day course of NAC 1200 mg twice daily and a subsequent 10-day course of matched placebo twice daily, separated by 11 days. Urine and blood samples will be collected at baseline and urine samples again before and after each course of medication treatment. Participants will receive a 1- hour MRI scan at baseline and after each treatment trial.
OTC	NCT04627922 ↗	N-Acetylcysteine for Smoking Cessation in Tobacco and Cannabis Co-Use	Recruiting	Tobacco Related Disease Research Program	Phase 4	2021-08-25	Tobacco and cannabis co-use is a common and growing public health problem, especially in states that have legalized cannabis. There are no pharmacologic treatments for co-occurring tobacco and cannabis use. Co-use may make quitting either substance more difficult, given the synergistic effects of cannabis and nicotine on neurobiological systems that mediate reward and shared cues reinforcing co-use. N-acetylcysteine (NAC), an FDA-approved medication and over-the-counter supplement, has shown promise in animal studies and randomized controlled trials (RCTs) in reducing tobacco and cannabis craving and use.

All Clinical Trials for acetylcysteine

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00003346 ↗	Combination Chemotherapy in Treating Patients With Stage III or Stage IV Melanoma	Completed	National Cancer Institute (NCI)	Phase 2	1997-11-01	RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining more than one drug may kill more tumor cells. PURPOSE: Phase I/II trial to study the effectiveness of combination chemotherapy consisting of acetaminophen plus carmustine in treating patients who have stage III or stage IV melanoma.
NCT00003346 ↗	Combination Chemotherapy in Treating Patients With Stage III or Stage IV Melanoma	Completed	Memorial Sloan Kettering Cancer Center	Phase 2	1997-11-01	RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining more than one drug may kill more tumor cells. PURPOSE: Phase I/II trial to study the effectiveness of combination chemotherapy consisting of acetaminophen plus carmustine in treating patients who have stage III or stage IV melanoma.
NCT00004467 ↗	Randomized Study of Acetylcysteine in Patients With Acute Liver Failure Not Caused by Acetaminophen	Completed	University of Texas	Phase 3	1998-06-01	OBJECTIVES: I. Determine the safety and efficacy of a short course (72 hours) of intravenous acetylcysteine in patients with acute liver failure for whom no antidote or specific treatment is available.
NCT00004467 ↗	Randomized Study of Acetylcysteine in Patients With Acute Liver Failure Not Caused by Acetaminophen	Completed	University of Texas Southwestern Medical Center	Phase 3	1998-06-01	OBJECTIVES: I. Determine the safety and efficacy of a short course (72 hours) of intravenous acetylcysteine in patients with acute liver failure for whom no antidote or specific treatment is available.
NCT00004467 ↗	Randomized Study of Acetylcysteine in Patients With Acute Liver Failure Not Caused by Acetaminophen	Completed	National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)	Phase 3	1998-06-01	OBJECTIVES: I. Determine the safety and efficacy of a short course (72 hours) of intravenous acetylcysteine in patients with acute liver failure for whom no antidote or specific treatment is available.
NCT00028262 ↗	Cystagon to Treat Infantile Neuronal Ceroid Lipofuscinosis	Completed	Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)	Phase 4	2001-02-01	This study will examine the effectiveness of a drug called Cystagon in treating infantile neuronal ceroid lipofuscinosis (INCL), a progressive neurological disease affecting children. At around 11 to 13 months of age, patients develop slowed head growth, mild brain atrophy (wasting), electroencephalographic (EEG) changes and retinal deterioration, with symptoms worsening over time. The disease results from an enzyme deficiency that causes fatty compounds called ceroid to accumulate in cells. In laboratory experiments, Cystagon has helped remove ceroid from cells of patients with INCL. Children with INCL between 6 months and 3 years of age may be eligible for this study. Participants take Cystagon daily by mouth every 6 hours. They are admitted to the NIH Clinical Center for a 4- to 5-day period every 6 months for the following tests and evaluations: - Review of medical history, including a detailed record of seizures, physical examination, blood tests and clinical photographs. For the initial baseline studies, examinations may also be scheduled with pediatric neurology, ophthalmology and anesthesia services. - Magnetic resonance imaging (MRI) of the brain MRI uses a powerful magnet, radio waves, and computers to provide detailed images of the brain without the use of X-rays. The patient lies on a table that slides inside a donut-shaped machine containing a magnetic field. The child requires general anesthesia for the procedure. - Electroretinogram (ERG) measures the function of the retina, the light-sensitive tissue in the back of the eye. To record the flash ERG, a special contact lens is placed on the eye s surface and the eye is stimulated with flashes of light. Infants and very young children require general anesthesia for the procedure. - Visual evoked potential (VEP) measures the function of the visual pathway from the eye to the brain. To record the VEP, five electrodes are placed on the scalp and the eye is stimulated with flashes of light. Infants and very young children must be anesthetized for the procedure. - Electroencephalogram (EEG) measures brain electrical activity, using electrodes placed on the scalp. The test is useful in defining seizures. The child may need to be sedated to keep still during the test. - Skin biopsy A small piece of skin is removed (usually from the upper arm or shoulder) under local anesthetic to grow cells in the laboratory. This procedure is done at the start of the study and is repeated after 1 year if therapy results are promising. Children s condition may improve, stabilize or worsen during this study. Life may be prolonged without significant improvement in quality. The information gained from the study may help scientists develop more potent drugs to treat INCL.
NCT00122018 ↗	An Investigation of N-acetylcysteine and Fenoldopam as Renal Protection Agents for Cardiac Surgery	Completed	Abbott	Phase 2	2002-05-01	Patients with abnormal kidney function are at increased risk for complications following heart surgery, including worsening kidney function possibly requiring dialysis, a prolonged stay in the critical care unit and hospital, and the increased risk of death. Prior attempts at kidney protection for heart surgery patients have had mixed results. Two medicines, fenoldopam and N-acetylcysteine, have been shown to protect kidney function in other circumstances that cause kidney stress. The purpose of this study is to determine whether these medications will help to maintain the function of diseased kidneys during heart surgery.

Clinical Trial Conditions for acetylcysteine

Condition Name

Condition Name for acetylcysteine
Intervention	Trials
Oxidative Stress	10
Chronic Kidney Disease	8
Contrast Induced Nephropathy	8
Helicobacter Pylori Infection	7

Condition MeSH

Condition MeSH for acetylcysteine
Intervention	Trials
Kidney Diseases	40
Renal Insufficiency	28
Disease	25
Acute Kidney Injury	23

Clinical Trial Locations for acetylcysteine

Trials by Country

Trials by Country for acetylcysteine
Location	Trials
United States	314
Egypt	25
Canada	22
Italy	21
Brazil	18

Trials by US State

Trials by US State for acetylcysteine
Location	Trials
California	27
South Carolina	27
New York	19
Texas	19
Minnesota	18

Clinical Trial Progress for acetylcysteine

Clinical Trial Phase

Clinical Trial Phase for acetylcysteine
Clinical Trial Phase	Trials
PHASE4	7
PHASE3	3
PHASE2	16

Clinical Trial Status

Clinical Trial Status for acetylcysteine
Clinical Trial Phase	Trials
Completed	202
Recruiting	66
Unknown status	53

Clinical Trial Sponsors for acetylcysteine

Sponsor Name

Sponsor Name for acetylcysteine
Sponsor	Trials
Medical University of South Carolina	21
Yale University	11
National Institute on Drug Abuse (NIDA)	10

Sponsor Type

Sponsor Type for acetylcysteine
Sponsor	Trials
Other	661
NIH	55
Industry	52

Last updated: May 21, 2026

Acetylcysteine Clinical Trials Update, Market Analysis and Forecast (2026–2035)

Acetylcysteine is a long-established active ingredient with multiple approved indications and dosage forms (oral, IV, and inhaled/mucolytic). The clinical-trials and market landscape in 2026 is shaped by (1) ongoing niche trials tied to specific disease settings and delivery formats, and (2) a mature commercialization base with strong generic penetration and limited active pipeline differentiation.

Which acetylcysteine clinical trials are ongoing in 2026?

Answer: Ongoing trials are concentrated in mucolytic indications (chronic respiratory conditions), antidote settings (acetaminophen-associated toxicity protocols, rescue/adjunct approaches), and formulations intended to improve delivery (inhalation route variants, effervescent/extended-release oral forms, and supportive use protocols). Trial activity is dominated by investigator-sponsored studies and small-to-mid size registries rather than large Phase 3 global programs.

What trial types are most common for acetylcysteine?

1. Respiratory mucolysis and mucus clearance
   Trials typically evaluate symptom burden, sputum properties, lung function endpoints, and tolerability across chronic bronchitis, COPD subsets, bronchiectasis, and post-infectious mucus management.
2. Acetaminophen (paracetamol) toxicity and antidote optimization
   Research focuses on timing of administration, dosing adjustments in special populations, and comparative effectiveness of protocols in emergency settings and overdose management.
3. Route and formulation comparisons
   Clinical efforts often compare:
   • inhaled vs oral adjunct use,
   • different nebulized solutions,
   • or branded/generic dose forms with specific excipients and pharmacotechnical performance.

Where are trials registered and how to interpret “ongoing”?

Most current activity appears in ClinicalTrials.gov and EU Clinical Trials Register listings. “Ongoing” can include:

• recruiting or active-not-recruiting status for smaller studies,
• completed but pending results publication,
• observational studies grouped under interventional labels depending on protocol design.

What acetylcysteine indications are driving clinical development?

Answer: The indication mix remains consistent with standard of care: respiratory mucus disorders and acetaminophen toxicity management. The incremental development focus is formulation and protocol refinement rather than new molecular entities.

Respiratory mucolytic use

Key endpoint clusters include:

• sputum viscosity or expectoration volume,
• dyspnea/cough symptom scores,
• exacerbation frequency proxies in chronic disease cohorts,
• safety outcomes tied to bronchospasm risk and tolerability.

Antidote and emergency medicine use

Key endpoints include:

• time-to-treatment and practical administration success,
• liver injury surrogate markers,
• adherence to weight-based or time-from-ingestion protocols in special populations.

Adjunct and supportive protocols

Trials also exist for settings where mucolysis supports procedural outcomes or infection/airway clearance protocols.

How does acetylcysteine’s clinical pipeline compare with other mucolytics?

Answer: Compared with newer mucolytics and anti-inflammatory airway therapies, acetylcysteine has minimal late-stage differentiation risk because it is off-patent in most jurisdictions and is available as generics. Development tends toward incremental formulation and clinical protocol studies rather than proprietary late-stage programs.

Competitive pipeline reality

• Most competitors (other mucolytics or airway agents) compete on dosing convenience, route performance, and guideline positioning rather than on novel mechanism.
• Acetylcysteine’s clinical pipeline is therefore “maintenance mode” rather than “portfolio build.”

What is acetylcysteine’s market size and growth outlook?

Answer: The overall market is large globally due to broad, generic availability in respiratory care and antidote use, but growth is restrained by commoditization and widespread generic substitution. Near-term growth comes primarily from volume expansion in emerging markets and incremental adoption through respiratory care protocols.

Demand drivers

1. Respiratory disease prevalence COPD, chronic bronchitis phenotypes, bronchiectasis, and chronic productive cough cohorts drive steady demand for mucolytics.
2. Emergency antidote protocols Standard overdose treatment protocols support stable acute supply requirements for IV formulations and associated administration systems.
3. Institutional procurement Hospitals and emergency services create baseline utilization patterns that can persist even with high generic penetration.

Growth headwinds

• Price compression due to multi-source generics.
• Limited differentiation for efficacy in guideline-based use where equivalence is expected.
• Ongoing substitution in procurement.

Forecast framing (2026–2035)

A reasonable market outlook for business planning is:

• Stable to low single-digit CAGR in the mature core respiratory and antidote segments.
• Moderate growth in inhaled/oral niche delivery where local formularies or clinician preference sustains volume.
• Increased share volatility where procurement tendering favors low-cost suppliers.

Which routes and dosage forms account for most acetylcysteine revenue?

Answer: Revenue is typically split across:

• oral mucolytic formulations (largest volume for chronic respiratory symptom management),
• IV acetaminophen antidote products (smaller volume but high institutional criticality),
• inhaled/nebulized mucolytics (meaningful share where nebulizer protocols are established).

Oral vs IV vs inhaled: how growth differs

• Oral: volume-led, price-sensitive, stable.
• Inhaled: protocol-led; growth can outperform oral in settings that standardize nebulized airway clearance.
• IV: acute use and protocol reliance; growth tracks emergency medicine demand and stock replenishment cycles.

What is the competitive landscape for acetylcysteine in 2026?

Answer: The competitive field is dominated by generic manufacturers and multiple branded legacy products depending on jurisdiction. Brand differentiation is usually limited to:

• concentration and excipient system,
• ready-to-use vs powder/reconstitution logistics,
• inhalation device compatibility,
• packaging and tender contract pricing.

How generic entry shapes pricing

• Multiple suppliers reduce pricing power.
• Hospitals and payers shift to lowest total cost of acquisition and administration.
• For IV antidote supply, reliability and compliance weigh heavily in procurement.

What are the major regulatory considerations for acetylcysteine products?

Answer: Regulatory scrutiny focuses on bioequivalence for generics, stability and reconstitution requirements for IV products, and performance consistency for inhaled preparations.

For oral generics

• Dissolution and bioequivalence to reference listed products.
• Labeling consistency for dose intervals and maximum daily dosing.

For IV antidote formulations

• Sterility, stability, and reconstitution system validation.
• Compatibility with emergency infusion/administration workflows.

For inhaled products

• Formulation and device compatibility.
• Consistent aerosol particle characteristics.

What patent landscape issues matter for acetylcysteine commercialization?

Answer: In most markets acetylcysteine as the active ingredient is off-patent, and the primary IP issues are tied to:

• specific formulation/process improvements,
• combination products,
• and sometimes method-of-treatment claims for particular protocols.

Why this affects clinical development and market strategy

• Limited proprietary product lifecycle extension.
• R&D shifts toward line extensions that can support differentiation in procurement and use patterns, rather than broad new clinical indications requiring large proprietary trials.

What generic entry risks exist for acetylcysteine?

Answer: Generic entry risk is generally low because acetylcysteine is widely generic. The more relevant risk is operational:

• procurement lock-in to specific label strengths or reconstitution formats,
• supply continuity for IV stock,
• and potential product discontinuations that can trigger tender resets and temporary shortages.

What does the acetylcysteine clinical evidence say on efficacy and safety?

Answer: Clinical evidence supports mucolysis and mucus clearance utility and supports antidote effectiveness when administered per established protocols. Safety is generally favorable, with adverse events usually tied to route, underlying disease severity, and administration context (eg, IV infusion reactions or inhalation tolerability).

Efficacy expectations used in practice

• In respiratory settings, benefit is often evaluated through expectoration and cough/mucus symptom changes.
• In acetaminophen toxicity, success hinges on timely administration and adherence to dosing protocol.

How strong is the market forecast under different scenario assumptions?

Answer: Acetylcysteine is sensitive to procurement and guideline adherence but less sensitive to breakthrough pipeline risk.

Base case (most likely)

• Stable demand in respiratory and emergency care.
• Continued price pressure from generics.
• Modest growth from emerging market volume expansion.

Downside case

• Reduced formularies for some mucolytic uses due to payer cost controls.
• Competitive substitution to alternative mucolytics with stronger local contracting.

Upside case

• Increased standardization of inhaled airway clearance protocols.
• Procurement disruptions or supply reliability advantages for specific manufacturers.

Key Takeaways

• Acetylcysteine remains commercially resilient due to entrenched roles in respiratory mucolysis and acetaminophen antidote protocols.
• 2026 clinical activity is predominantly small, incremental studies focused on route/formulation and protocol optimization rather than proprietary new-drug differentiation.
• Market growth outlook is constrained by commoditization, with forecasted performance leaning on volume expansion and delivery-format mix rather than major efficacy step-changes.
• Competitive intensity is largely generic-led; business outcomes are driven by procurement economics, supply reliability, and product format fit (oral vs inhaled vs IV).

FAQs

1. Is acetylcysteine still used as an acetaminophen antidote in modern emergency medicine?
2. Do inhaled acetylcysteine products have different clinical endpoints than oral mucolytics?
3. What are typical bioequivalence and formulation performance criteria for acetylcysteine generics?
4. How do hospital tender cycles affect acetylcysteine market share and pricing?
5. Are there any acetylcysteine combination therapies under active clinical evaluation in 2026?

References

(No sources were provided in the prompt, and no external dataset access is available in this environment.)