Disease × agent evidence record

N-acetylcysteine (NAC) for COPD: evidence, trials and status

N-acetylcysteine (NAC) has both completed registered trials and synthesis-level publications linked to COPD. That is the strongest profile in this database, but the summaries here do not extract effect sizes, so read the linked reviews for direction and magnitude of benefit.

8 registered trials 1 recruiting 14 publications Evidence tier C · Preliminary Score 63.5
Research Tracker › Pairs › COPD › N-acetylcysteine (NAC)
Research map, not treatment advice. This page aggregates registry and literature records. It does not evaluate efficacy, dosing or safety for any individual. Discuss any treatment decision with a qualified clinician.

Summary

N-acetylcysteine (NAC) has reached Preclinical as its most advanced recorded development stage across any indication, and the database holds no approval for COPD. ClinicalTrials.gov lists 8 registered trials linking N-acetylcysteine (NAC) to COPD: 1 is currently recruiting; 5 have completed; 2 are terminated, withdrawn, suspended or of unknown status. The most advanced is Phase 4 (NCT00184977). The largest enrolment is 333 participants (NCT03843541). Registration activity spans 1997 to 2024. The literature layer holds 14 publications for this pair: 3 Cochrane reviews, 3 meta-analyses, 2 systematic reviews, 1 randomised controlled trial publication and 5 clinical trial publications. Publication years run from 2014 to 2024. Because at least one synthesis-level source exists (systematic review, meta-analysis or Cochrane review), this pair has been assessed beyond single studies, although the synthesis may concern a different indication.

The RepurpOS disease-intelligence file for Chronic Obstructive Pulmonary Disease ranks 505 candidate therapeutics from Open Targets, ChEMBL, DGIdb and PubMed; only a minority carry direct clinical evidence, and this page covers one of those. Spontaneous remission context recorded for the condition: Effectively zero — airflow obstruction is irreversible by definition in COPD; FEV1 decline continues at 30-60 mL/year on standard care.

Open in Repurposing ExplorerAgent page: N-acetylcysteine (NAC)COPD hubCOPD biomarkers & interventionsOSMF ReviewCitation

Evidence table

Evidence tierC · Preliminary
Evidence score63.5 (trials 28.5, literature 30.0, tier 5, approved bonus 0.0)
Registered trials8 total: 1 recruiting, 0 active / not yet recruiting, 5 completed, 2 other
Linked publications14 (5 clinical trial publications, 3 Cochrane reviews, 3 meta-analyses, 2 systematic reviews, 1 randomised controlled trial publication)
Agent typeSupplement
Development stage (any indication)Preclinical
Mechanism / classHerbal medicine for COPD · Halma MTJ, Saleeby Y, Tuszynski J · 2024
Data sourcesOSMF Chronic Disease Review
How the evidence score is calculated
  • Each registered trial scores by status (recruiting / active / enrolling 3, completed 2.5, not yet recruiting 2, unknown 1, terminated / withdrawn / suspended 0.5) plus a phase bonus (phase 3-4 +2, phase 2 +1, phase 1 +0.5). The trial component is capped at 30.
  • Each literature item scores by design (Cochrane review 5, meta-analysis 4, systematic review 3, RCT 3, clinical trial publication 2, curated reference 1.5, other PubMed record 1). The literature component is capped at 30.
  • The existing evidence tier adds 15 (A / Strong), 10 (B / Moderate), 5 (C / Preliminary) or 0 (D / Anecdotal).
  • Agents approved for any indication (max clinical phase 4) add 5, because an approved agent has an established safety profile that lowers the barrier to repurposing trials.
  • The score ranks what has been studied, not what works. It does not read effect sizes or directions of effect.

Registered clinical trials

NCT IDTitleStatusPhaseEnrolment
NCT01136239The Effect of High Dose N-acetylcysteine on Airtrapping and Airway Resistance in Chronic Obstructive Pulmonary Disease (COPD) Patients
2010
completedPhase 4133
NCT02579772Effects of N-acetylcysteine on Cardiorespiratory Control in COPD Patients With Mild-to-moderate Airflow Obstruction
2015
completedPhase 413
NCT00184977COPD on Primary Care Treatment (COOPT)
1998
completedPhase 4270
NCT06152653The Effects of Positive Airway Pressure on the Mucolytic Effects of NAC (TEAM)
2024
recruitingPhase 440
NCT03843541A Clinical Trial to Compare the Efficacy and Safety of 1-week Treatment of Intravenous N-acetylcysteine (NAC) 600 mg Twice Daily, Ambroxol Hydrochloride 30 mg Twice Daily and Placebo as Expectorant Therapies in Adult Chinese Patients With Respiratory Tract Diseases and Abnormal Mucus Secretions
2019
completedPhase 3333
NCT00205647Study of Expectorant Activity of Oral N-acetylcystein (NAC) in Patients With Stable Chronic Bronchitis
1997
completedPhase 2240
NCT04798118Role of Toilet Bronchoscopy in RICU
2022
status unknownNot applicable130
NCT01599884N-Acetylcysteine for Patients With COPD and ChronicBronchitis
2012
status unknownNot applicable65

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Published literature

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Mechanism and notes

Recorded mechanism or class: Herbal medicine for COPD · Halma MTJ, Saleeby Y, Tuszynski J · 2024.

OSMF's existing evidence tier for this pair is C (Preliminary), derived from the strength of the disease association recorded in OSMF Chronic Disease Review. The tier describes how well the drug-disease link is documented, not how well the drug works.

Frequently asked questions

Is N-acetylcysteine (NAC) approved for COPD?

N-acetylcysteine (NAC) has reached Preclinical as its most advanced recorded development stage across any indication, and the database holds no approval for COPD. Approval status for the specific indication should always be confirmed with the relevant regulator and prescribing information.

Is N-acetylcysteine (NAC) in clinical trials for COPD?

ClinicalTrials.gov lists 8 registered trials linking N-acetylcysteine (NAC) to COPD: 1 is currently recruiting; 5 have completed; 2 are terminated, withdrawn, suspended or of unknown status. The most advanced is Phase 4 (NCT00184977). The largest enrolment is 333 participants (NCT03843541). Registration activity spans 1997 to 2024.

What does the evidence show for N-acetylcysteine (NAC) in COPD?

N-acetylcysteine (NAC) has both completed registered trials and synthesis-level publications linked to COPD. That is the strongest profile in this database, but the summaries here do not extract effect sizes, so read the linked reviews for direction and magnitude of benefit. OSMF's existing evidence tier for this pair is C (Preliminary), derived from the strength of the disease association recorded in OSMF Chronic Disease Review. The tier describes how well the drug-disease link is documented, not how well the drug works.

Cite this page

Open Source Medicine Foundation. N-acetylcysteine (NAC) for COPD: evidence, trials and status. OSMF Research Tracker. Updated 2026-07-05. https://research.opensourcemed.info/pairs/chronic-obstructive-pulmonary-disease/n-acetylcysteine-nac.html

Data: ClinicalTrials.gov, PubMed, Open Targets, ChEMBL, DGIdb and the OSMF therapeutic agent database. Last updated 2026-07-05. Page built 2026-10-07.

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This is a research map, not treatment advice. Evidence tiers and scores summarise what has been studied, not whether a treatment works or is safe for you.