This page shows what was measured, who it was measured in, and what that does not settle.
What Acetylcysteine does in the body
The antidote for a paracetamol overdose, and a very old drug for loosening thick mucus
Acetylcysteine carries a sulfur atom with a spare hydrogen on it, and that one chemical group does everything. In mucus, the sulfur breaks the bridges that hold the sticky protein chains together, so the mucus becomes runnier. In the liver, the same molecule is taken apart and used as the raw material for glutathione, the compound the liver uses to mop up the poisonous by-product of too much paracetamol. There is no receptor and no signalling — it is chemistry, and that is exactly why it works so well where the chemistry is the problem and so poorly everywhere else.
What happened in people
No difference in death, dialysis or persistent creatinine rise at 90 days after angiography in 4,993 patients (OR 1.02)
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The recorded finding that sits closest to something a person would notice. Written into the record, not signed off, and it carries no population or interval.
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
The clearest illustration in this file of the difference between a mechanism you can write as an equation and a mechanism you can only write as a hypothesis
Where it acts
The mucus layer sitting in the airway lumen, and the cytosol of the liver cell where glutathione is made
Kind of result
Living longer, or avoiding a major event
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · WYQ7N0BPYC · read 2026-08-29
The supplement label database classes it as non-nutrient/non-botanical, under the name N-Acetyl Cysteine.
No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.
Shown as the opening line on this page.
A limit recorded against this substance. Not signed off as a reviewed claim.
The four opening statements run to 137 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Stand-in result
A stand-in result is a number measured because the real result takes too long.
A picture of it, and where the picture fails
It is like judging a journey by the speedometer rather than by arriving.
Where that stops being true. Speed does predict arrival. Many stand-in results do not predict the real one.
What people get wrong. A stand-in result is often reported as the result itself.
A surrogate endpoint substituted for a clinical endpoint, valid only where the substitution has been shown to hold.
Randomisation
Randomisation means chance decides who gets which treatment.
A picture of it, and where the picture fails
It is like a coin toss deciding the groups.
Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.
What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.
Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.
Confidence interval
A confidence interval is the range the true answer is likely to sit in.
A picture of it, and where the picture fails
It is like a weather forecast giving a range rather than one number.
Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.
What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.
An interval estimate that would contain the true parameter in a stated proportion of repeated studies.
Pathway
A pathway is a chain of steps inside a cell, each one setting off the next.
A picture of it, and where the picture fails
A pathway is like a row of dominoes.
Where that stops being true. Dominoes fall one way. Pathways loop back and can switch themselves off.
What people get wrong. Changing one step is read as changing the outcome. Other steps often absorb it.
An ordered series of molecular interactions producing a defined cellular change.
What happened in people◇Read from sources, not yet reviewed
What was measured, goal by goal
One row for each goal a registered study measured something for. One column for each kind of thing that could be measured.
Registered studies list 40 outcome measures that RNAWiki could read. A registered study says what someone planned to measure. It does not say what they found. 0 of the matched studies tested this substance, and 0 posted a result.
There is no single score. A strong test result and a weak life result are different facts.
Goals down the side, kinds of measurement across the top. Each cell says what kind of thing was registered, not what was found.
Goal
Life outcome
What a body can do
How a person feels
A test result
A step in the body
Harms
How long
Who was studied
Energy
∅Nothing in the sources checkedNo registered study lists a life outcome for this goal.
∅Nothing in the sources checkedNo registered study lists a performance measure for this goal.
…Waiting for a reviewer1 registered symptom measure.
∅Nothing in the sources checkedNo registered study lists a test result for this goal.
∅Nothing in the sources checkedNo registered study lists a body-step measure for this goal.
—Not recordedHarms were not a registered measure for this goal.
—Not recordedNo finished study window is recorded.
…Waiting for a reviewerWho was studied is listed further down the page.
Which registered measures put each goal on this table
Energy
fatigue severity scale
Sorted by fixed word lists, version v1. A name the rules do not recognise stays unsorted rather than moving to the nearest column.
What each mark on this table means
∅ Nothing in the sources checked
No registered study lists a life outcome for this goal.
… Waiting for a reviewer
1 registered symptom measure.
— Not recorded
Harms were not a registered measure for this goal.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
Incidence of hepatotoxicity after acetaminophen overdose, by risk category and by interval from ingestion to treatment
✓ The study showed what it set out to show
Who was studied
National multicentre oral acetylcysteine series 1976-1985 (N Engl J Med 1988;319:1557-1562)
How many people
2540
Study design
Open, uncontrolled multicentre series with historical-control comparison
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Hepatotoxicity 6.1% at probable risk when treated within 10 hours against 26.4% at 10 to 24 hours; 41% in high-risk patients treated at 16 to 24 hours against higher historical-control rates; 11 deaths among 2,540 (0.43%)
Repeated elsewhere
Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. There was no randomised placebo arm and there never has been. The comparison for the late high-risk group is historical controls. The dose-timing gradient is what carries the causal inference, and it is strong, but the design is not one that would satisfy a modern regulator for a new drug.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Sterile unpreserved 10% and 20% solution for nebulisation, direct instillation or oral administration; a separate intravenous formulation for the antidote indication; and effervescent tablets
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
Yearly reduction in FEV1 and number of exacerbations per year in chronic obstructive pulmonary disease
✗ The study did not show it
Who was studied
BRONCUS (Lancet 2005;365:1552-1560)
How many people
523
Study design
Phase 3, randomised, placebo-controlled, 50 centres, 3 years
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
FEV1 decline 54 mL (SE 6) against 47 mL (SE 6), slope difference 8 mL (SE 9), 95% CI -25 to 10; exacerbations 1.25 (SD 1.35) against 1.29 (SD 1.46) per year, HR 0.99 (95% CI 0.89 to 1.10), p=0.85
Repeated elsewhere
Replicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. Subgroup analysis suggested exacerbations might fall in patients not on inhaled corticosteroids, and a secondary analysis suggested an effect on hyperinflation. Both are post-hoc findings from a trial whose co-primary endpoints were flat, and neither has been confirmed in a trial built to test it.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Sterile unpreserved 10% and 20% solution for nebulisation, direct instillation or oral administration; a separate intravenous formulation for the antidote indication; and effervescent tablets
Interval reported. 95% CI -25 to 10; exacerbations 1
Written into the record, not signed off as a reviewed claim.
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
Change in forced vital capacity over 60 weeks in idiopathic pulmonary fibrosis with mild to moderate impairment
✗ The study did not show it
Who was studied
PANTHER-IPF (NCT00650091, N Engl J Med 2012;366:1968-1977 and 2014;370:2093-2101)
How many people
264
Study design
Phase 3, randomised, double-blind, placebo-controlled, three arms then two
Compared against
A dummy treatment
Kind of result
What a body can do day to day
What was found
Acetylcysteine alone against placebo at 60 weeks: FVC -0.18 L against -0.19 L, p=0.77; death 4.9% against 2.5%, p=0.30; acute exacerbation 2.3% in each group
Repeated elsewhere
Replicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. The three-drug arm was terminated at interim analysis for 8 deaths against 1 (p=0.01) and 23 hospitalisations against 7 (p<0.001) with no evidence of benefit. The regimen stopped had been widely used as standard care for idiopathic pulmonary fibrosis before the trial ran.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Sterile unpreserved 10% and 20% solution for nebulisation, direct instillation or oral administration; a separate intravenous formulation for the antidote indication; and effervescent tablets
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
Composite of death, need for dialysis, or persistent increase of at least 50% from baseline in serum creatinine at 90 days after angiography
✗ The study did not show it
Who was studied
PRESERVE (NCT01467466, N Engl J Med 2018;378:603-614)
How many people
5177
Study design
Phase 3, randomised, two-by-two factorial, placebo-controlled, stopped at interim
Compared against
A dummy treatment
Kind of result
Living longer, or avoiding a major event
What was found
114 of 2,495 (4.6%) on acetylcysteine against 112 of 2,498 (4.5%) on placebo; odds ratio 1.02 (95% CI 0.78 to 1.33), p=0.88; no significant difference in contrast-associated acute kidney injury
Repeated elsewhere
Replicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. The trial’s own background states that both interventions were already widely used without definitive evidence of efficacy. The practice preceded the evidence by roughly fifteen years, and the evidence, when it came, was null.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Sterile unpreserved 10% and 20% solution for nebulisation, direct instillation or oral administration; a separate intravenous formulation for the antidote indication; and effervescent tablets
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
RNAWiki holds 4 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What happened in people◇Read from sources, not yet reviewed
How close this is to real life
The top step is something a person would feel or care about. The bottom is a guess from software. Filled steps are where evidence exists for this substance.
■Living longer, or avoiding a major eventEvidence recorded. Death, a heart attack, a stroke, a hospital stay.4 registered measures of this kind. 2 written-up studies measured this and did not show a benefit.
□What a body can do day to dayNo evidence recorded. Walking, dressing, breathing, recovering.No registered study measures this.
□Measured performanceNo evidence recorded. How much was lifted, how far was run, how fast.No registered study measures this.
■Symptoms and quality of lifeEvidence recorded. Pain, tiredness, mood, sleep, as the person rated it.4 registered measures of this kind.
■A number that stands in for healthEvidence recorded. Cholesterol, blood sugar, bone density. A stand-in, not the thing itself.6 registered measures of this kind.
■A step measured inside a personEvidence recorded. Something measured in human tissue or human cells.1 registered measure inside human tissue.
■AnimalsEvidence recorded. Mice, rats, dogs. Useful for ideas, not proof about people.Stored records in C. elegans (roundworm), Drosophila (fruit fly), Mouse. A result in animals says what to test next. It does not say what happens in people.
■Cells in a dishEvidence recorded. Cells or chemistry on a bench, far from a whole body.Stored mechanism abstracts describe steps measured in cells or tissue.
□A guess from softwareNo evidence recorded. Nobody measured it. RNAWiki never publishes one as a finding.RNAWiki stores no prediction for this record. Software can suggest a link. RNAWiki does not publish one as a finding.
Higher on these steps means closer to something a person would feel. It does not mean better done.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Start
Acetylcysteine
What a person takes: Sterile unpreserved 10% and 20% solution for nebulisation, direct instillation or oral administration; a separate intravenous formulation for the antidote indication; and effervescent tablets.
The measurement behind this step
Each millilitre of the 10% solution contains 100 mg of acetylcysteine and 0.25 mg of edetate disodium; the 20% contains 200 mg and 0.5 mg. pH is adjusted to 7.0 within a 6.0 to 7.5 range with sodium hydroxide and, if needed, hydrochloric acid. The solution is oxygen sensitive and not for injection. Continued nebulisation with a dry gas concentrates the drug by evaporation, which the label says can impede delivery and should be corrected by dilution with sterile water.
Getting in
One sulfur atom does all the work
Acetylcysteine is the amino acid cysteine with a small chemical cap on it. Everything the drug does comes from the sulfur group hanging off the side.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
N-acetyl-L-cysteine, molecular weight 163.19, a white crystalline powder melting at 104 to 110 degrees Celsius, supplied as unpreserved 10% or 20% solutions at pH 7.0 with edetate disodium. The solution is oxygen sensitive because the free thiol oxidises to the disulfide dimer diacetylcystine.
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
Nebulised into the lung, it works on the mucus sitting in the airway, not on the tissue underneath.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Mucus viscosity depends on mucoprotein concentration and, to a lesser extent, DNA, the latter rising with purulence from cellular debris. Acetylcysteine acts extracellularly on the mucin polymer. Its activity is unaltered by the presence of DNA and increases with pH, with significant mucolysis between pH 7 and 9.
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
Long protein chains in mucus are stitched to each other by sulfur-to-sulfur bonds. The drug’s own sulfur breaks those stitches and the mucus thins.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
The label attributes mucolysis to the sulfhydryl group, which it says probably opens disulfide linkages in mucus, lowering viscosity. The hedge is in the original text and has never been removed. Whether thinner mucus changes any clinical outcome is a separate question the indication list does not answer.
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
Swallowed or infused, it is taken apart and rebuilt as glutathione
The body strips the cap off and uses the cysteine to make glutathione, the molecule the liver needs to neutralise the toxic by-product of a paracetamol overdose.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Rapid deacetylation in vivo yields cysteine, the rate-limiting substrate for glutathione synthesis. After an overdose of 150 mg/kg or more of acetaminophen, sulfate and glucuronide conjugation saturate and cytochrome P-450 produces enough reactive intermediate to deplete hepatic glutathione; the intermediate then binds hepatocyte macromolecules. Restoring glutathione restores conjugation to the non-toxic cysteine and mercapturic acid derivatives excreted by the kidney.
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
The liver is protected, and the clock decides how well
Started within eight hours it works whatever the blood level. Started later, the protection falls away.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Hepatotoxicity in 6.1% of at-risk patients treated within 10 hours against 26.4% at 10 to 24 hours; 41% in high-risk patients treated at 16 to 24 hours, still below historical controls. Protective regardless of initial plasma acetaminophen concentration within eight hours, with no difference between starting at zero to four and four to eight hours.
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
Everywhere else the antioxidant argument has failed
Three big randomised trials in three organs — lungs in COPD, lungs in fibrosis, kidneys after a scan — and none of them found a benefit.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
COPD over three years: FEV1 decline 54 against 47 mL per year, exacerbations HR 0.99 (95% CI 0.89 to 1.10). Idiopathic pulmonary fibrosis over 60 weeks: FVC change -0.18 against -0.19 L, p=0.77. Contrast angiography at 90 days: composite of death, dialysis or persistent creatinine rise 4.6% against 4.5%, OR 1.02 (95% CI 0.78 to 1.33).
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 6 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What it would be like to take◇Read from sources, not yet reviewed
Felt, measured, or meaningful
Three different things that get called the same word. Registered studies measured all three, and mixing them is how a blood test becomes a health claim.
Felt
Things a person could notice without a test.
exacerbations of copd condition specific quality of life
clinical global impression severity
clinical global impression improvement
fatigue severity scale
Measured
Things only a test, a scale or a device shows.
arterial blood pressure decrease
post operative plasma il 6
nac concentrations
maternal and infant mean blood pressure change
cerebral blood flow
urinary albumin excretion
brachial artery flow mediated dilation
Meaningful
Things that change how a life goes, not only a number.
overall survival rate
survival
survival at 2 years
graft survival
A registered study says what someone planned to measure. It does not say what they found. A number moving is not the same as a life going better. The two are shown apart here.
Felt, but not shown to help. A person notices a change. No study showed it leads anywhere good.
Measured, but not felt. A number moves. The person notices nothing. Both can be true.
Measured, but not shown to matter. A number moves in the good direction. Nobody showed that lives went better.
Matters, but takes years. The result that counts may take longer than anyone would keep watching.
Names that fit none of the three (25)
prevention of pulmonary mucus obstruction
endothelial function
incidence of acute renal failure
development of contrast induced nephropathy
hearing thresholds
proteinuria
alcohol consumption
nac terminal elimination half life
nac volume of distribution
nac total body clearance
placental transfer
prothrombin time
contrast induced nephropathy incidence
carbon monoxide levels
therapeutic benefit
contrast induced nephropathy
gestational age at delivery
sinonasal outcomes test 22
peritoneal membrane function
intracellular glutathione level
These are harms, study-process measures, or names the rules did not recognise. They are shown rather than dropped.
What it would be like to take◇Read from sources, not yet reviewed
How long anything takes
Nine different lengths of time that get confused with each other. None of them is worked out from another.
Before anything is noticed.RNAWiki does not store this separately, and never works it out from another figure on this page.
Before a test result moves.RNAWiki does not store this separately, and never works it out from another figure on this page.
Before performance moves.RNAWiki does not store this separately, and never works it out from another figure on this page.
How long the result was watched.No finished study window is recorded for a study that tested this substance.
How long people took it.How long people actually took it is not stored. The study window is not the same thing.
How long people were followed.Follow-up length is not stored separately. It is never read off the study window, which would be a different thing.
How fast the body clears it. 5.6 hours hours
Read from the label, which states: “Elimination: After a single intravenous dose of acetylcysteine, the plasma concentration of total acetylcysteine declined in a poly-exponential decay manner with a mean terminal half-life (T 1/2 ) of 5.6 hours.”
How long effects linger.RNAWiki does not store this separately, and never works it out from another figure on this page.
Beyond the studies. Nothing is recorded about the long term.
The longest finished study sets the edge of what anyone measured.
A study window is not how long people took it, and neither is how long they were followed. Where RNAWiki holds only one of the three, it shows one.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
People who have taken too much paracetamol, where it is standard of care worldwide; and, far less usefully, people with thick airway secretions.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “Elimination of acetylcysteine was slower in these infants than in adults; mean elimination half-life was 11 hours.”
US prescribing information · 8cca4e4c-85a2-d575-e053-2995a90a6599 · read 2026-08-30
On older people, the label states: “The clinical studies do not provide a sufficient number of geriatric subjects to determine whether the elderly respond differently.”
US prescribing information · 8cca4e4c-85a2-d575-e053-2995a90a6599 · read 2026-08-30
On people who are pregnant, the label states: “Category B There are no adequate and well-controlled studies of Acetylcysteine Injection in pregnant women.”
US prescribing information · 8cca4e4c-85a2-d575-e053-2995a90a6599 · read 2026-08-30
On people who are breastfeeding, the label states: “It is not known whether Acetylcysteine Injection is present in human milk.”
US prescribing information · 8cca4e4c-85a2-d575-e053-2995a90a6599 · read 2026-08-30
Where the result stopped carrying
COPD: three years of treatment changed neither lung function decline nor exacerbations
Idiopathic pulmonary fibrosis: the standard three-drug regimen was stopped for excess death and hospitalisation, and acetylcysteine alone then did nothing
Contrast-associated kidney injury: null on every endpoint in the largest trial ever run on the question
The inhaled mucolytic itself can produce unpredictable, sometimes severe airway obstruction in the patients it is indicated for, and the label says reactors cannot be identified in advance
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied for a different goal
The studies measured something else entirely.
On this record: Some registered studies measured things that match no goal on this page.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (10)
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Given by a clinician
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Sterile unpreserved 10% and 20% solution for nebulisation, direct instillation or oral administration; a separate intravenous formulation for the antidote indication; and effervescent tablets
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
RNAWiki has not recorded a supervision or regulatory status for this substance.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
No register row and no identity class settled the question.
No source is stored against this line.
What is in the pack
5 mg. 5 range with sodium hydroxide and, if needed, hydrochloric acid. The solution is oxygen sensitive and not for injection. Continued nebulisation with a dry gas concentrates the drug by evaporation, which the label says can impede delivery and should be corrected by dilution with sterile water.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold and what that means for what is in the pack.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
Contraindicated only in known sensitivity. Inhaled acetylcysteine can produce increased airways obstruction of varying and unpredictable severity; reactors cannot be identified in advance and prior tolerance does not predict future tolerance. Asthmatics must be watched carefully, bronchodilator relief is usually rapid, and progression requires immediate discontinuation. Liquefied secretions may need mechanical suction if cough is inadequate. Reported effects include stomatitis, nausea, vomiting, fever, rhinorrhoea, drowsiness, clamminess, chest tightness and bronchoconstriction. Oral dosing in the large amounts needed for overdose commonly causes nausea and vomiting. Generalised urticaria has been observed rarely with oral use for overdose, and treatment should stop unless it is essential and the symptoms can be controlled. If hepatic encephalopathy becomes evident the label directs discontinuation to avoid further nitrogenous load.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Where this came from
Acetylcysteine solution United States prescribing information — Description, Clinical Pharmacology (mucolytic and antidotal), Indications and Usage, Contrain… · a recorded source, not a stored snapshot
These are reports people sent to a regulator. They do not show the medicine caused the reaction.
Nobody counted how many people took the medicine and reported nothing.
The same event can be reported more than once, and many reports are incomplete.
News coverage, lawsuits and new warnings change how often people report.
A count is not a rate and not a risk.
Acetylcysteine appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 594 reaction mentions were counted. One report can name several reactions.
The recorded terms (10)
acute kidney injury — 149 reaction mentions
dyspnoea — 92 reaction mentions
pruritus — 62 reaction mentions
stevens-johnson syndrome — 57 reaction mentions
toxicity to various agents — 46 reaction mentions
nephropathy toxic — 45 reaction mentions
erythema — 42 reaction mentions
urticaria — 42 reaction mentions
anaphylactoid reaction — 30 reaction mentions
asthma — 29 reaction mentions
open-targets-adr · recorded 2026-06-24 · a recorded source, not a stored snapshot
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Sterile unpreserved 10% and 20% solution for nebulisation, direct instillation or oral administration; a separate intravenous formulation for the antidote indication; and effervescent tablets
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
5 mg. 5 range with sodium hydroxide and, if needed, hydrochloric acid. The solution is oxygen sensitive and not for injection. Continued nebulisation with a dry gas concentrates the drug by evaporation, which the label says can impede delivery and should be corrected by dilution with sterile water.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on which forms are sold and how they compare.
No source is stored against this line.
What is recorded as being sold
54 products list this as an active ingredient in the United States drug directory. 52 of them contain it and nothing else.
FDA National Drug Code directory · 12598-7027 · read 2026-08-29
They are sold as inhalant, injection, injection, solution, pellet, powder and solution, taken intravenous, oral and respiratory (inhalation).
FDA National Drug Code directory · 12598-7027 · read 2026-08-29
The regulator's established pharmacologic class for it is antidote [epc], antidote for acetaminophen overdose [epc] and decreased respiratory secretion viscosity [pe].
FDA National Drug Code directory · 12598-7027 · read 2026-08-29
22 published labels name it as an active ingredient. 20 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 8cca4e4c-85a2-d575-e053-2995a90a6599 · read 2026-08-29
Those labels are classed as human otc drug and human prescription drug.
US prescribing information · 8cca4e4c-85a2-d575-e053-2995a90a6599 · read 2026-08-29
3105 marketed supplement labels list this ingredient, classed as non-nutrient/non-botanical.
Those labels carry all other and structure/function claims. A claim of that kind is written by the manufacturer and is not assessed by any regulator, so its presence says nothing about whether it is true.
Acetylcysteine is intravenous at 3 DOSAGE FORMS AND STRENGTHS Each single dose vial contains 6g/30mL (200 mg/mL) of Acetylcysteine., recorded as fda label in effect 2022-10-31 in the United States.
US prescribing information · 8cca4e4c-85a2-d575-e053-2995a90a6599 · read 2026-08-30
Recorded price in US: 0.63509–2.61887 USD per one millilitre, across 18 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.
Questions worth asking
Which of the trials of Acetylcysteine studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That being a glutathione precursor and an antioxidant translates into benefit wherever oxidative stress is implicated — tested on hard endpoints in three organs and negative in all three
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That thinner mucus is a clinical benefit, which the 1963 mucolytic indication list assumes and no outcome trial has shown
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the BRONCUS subgroup of patients not on inhaled corticosteroids identifies a responsive population, on a post-hoc analysis of a flat primary endpoint
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That routine pre-angiography dosing protects kidneys, a practice adopted for roughly fifteen years before the definitive trial found nothing
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Acetylcysteine are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
As a paracetamol antidote it is one of the clearest wins in medicine
In plain words
Across 2,540 treated overdoses, liver injury occurred in 6% of at-risk patients treated within ten hours and 26% of those treated between ten and twenty-four hours. Nobody clearly died of paracetamol if the antidote was started within sixteen hours.
What was measured
Incidence of hepatotoxicity by time from ingestion to start of treatment, in patients at probable and high risk
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The national multicentre study analysed outcomes in 2,540 patients treated with oral acetylcysteine — a 140 mg/kg loading dose followed four hours later by 70 mg/kg every four hours for 17 further doses — out of 11,195 reported suspected overdoses between 1976 and 1985. Hepatotoxicity developed in 6.1% of patients at probable risk when acetylcysteine was started within 10 hours of ingestion and in 26.4% when it began 10 to 24 hours afterwards. Among high-risk patients treated 16 to 24 hours after overdose, hepatotoxicity developed in 41%, lower than in historical controls. Within eight hours the drug was protective regardless of initial plasma acetaminophen concentration, and there was no difference between starting at zero to four or four to eight hours. There were 11 deaths among 2,540 patients (0.43%), and in the nine fatal cases with a pre-treatment aminotransferase, it was already elevated. No deaths were clearly caused by acetaminophen in anyone whose treatment began within 16 hours. The mechanism is set out in the label: a small fraction of an acetaminophen dose is oxidised by cytochrome P-450 to a reactive intermediate that conjugates with hepatic glutathione, and after an overdose of 150 mg/kg or greater the conjugation pathways saturate and glutathione is depleted. Acetylcysteine supplies the cysteine to rebuild it.
Written into the record, not signed off as a reviewed claim
The best-evidenced drug in this file has never had a placebo-controlled trial
In plain words
The 2,540-patient study that established the antidote was uncontrolled, compared against historical rates. No randomised trial was run, because by the time anyone could have, withholding it would have been unethical.
What was measured
That the antidote benefit is causal — an inference from an uncontrolled series with a strong dose-timing gradient, universally accepted and never randomised
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The national multicentre study was an open series of patients treated during the investigational use of oral acetylcysteine, analysed by initial plasma acetaminophen concentration and by delay to treatment, with comparison to historical controls for the high-risk late-treatment group. There is no randomised placebo-controlled trial of acetylcysteine for acetaminophen overdose and there never will be. This is not a criticism — it is the correct outcome, and the effect size and the dose-timing gradient are about as convincing as uncontrolled data can be. It is included as an audit because it sets the standard by which the rest of this page should be read. Where the mechanism is specific, stoichiometric and matched to a defined toxin, historical-control evidence has been enough to make a drug standard of care worldwide. Where the mechanism is the general claim that an antioxidant should help, three large randomised trials have been run and all three were negative.
Written into the record, not signed off as a reviewed claim
In COPD, three years of treatment changed nothing
In plain words
Five hundred and twenty-three people with chronic obstructive lung disease took acetylcysteine or placebo for three years. Lung function declined at the same rate and they had the same number of flare-ups.
What was measured
Yearly rate of FEV1 decline and exacerbations per year over three years
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
BRONCUS randomised 523 patients with COPD across 50 centres to 600 mg daily acetylcysteine or placebo, followed for three years, with co-primary outcomes of yearly FEV1 decline and exacerbations per year, analysed by intention to treat. The yearly rate of FEV1 decline was 54 mL (SE 6) on acetylcysteine against 47 mL (SE 6) on placebo — a difference in slope of 8 mL (SE 9), 95% CI -25 to 10, favouring neither. Exacerbations per year were 1.25 (SD 1.35) against 1.29 (SD 1.46), hazard ratio 0.99 (95% CI 0.89 to 1.10, p=0.85). The authors concluded acetylcysteine is ineffective at preventing deterioration in lung function and preventing exacerbations in COPD. A subgroup analysis suggested exacerbations might be reduced in patients not taking inhaled corticosteroids, and a secondary analysis suggested an effect on hyperinflation — both are the kind of finding that appears when a primary endpoint is flat, and neither has been confirmed in a trial designed to test it.
Written into the record, not signed off as a reviewed claim
In pulmonary fibrosis the standard regimen was killing people
In plain words
Prednisone, azathioprine and acetylcysteine was the accepted treatment for idiopathic pulmonary fibrosis. When it was finally tested against placebo, the trial was stopped early: eight deaths against one, twenty-three hospitalisations against seven. Acetylcysteine on its own was then tested and did nothing.
What was measured
Deaths and hospitalisations at the interim analysis, and change in forced vital capacity at 60 weeks
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
PANTHER-IPF randomised patients with idiopathic pulmonary fibrosis and mild to moderate lung-function impairment 1:1:1 to prednisone plus azathioprine plus acetylcysteine, to acetylcysteine alone, or to placebo, with the primary outcome being change in forced vital capacity over 60 weeks. At a planned interim analysis with about half the data collected — 77 patients on combination therapy and 78 on placebo — the combination arm had 8 deaths against 1 (p=0.01) and 23 hospitalisations against 7 (p<0.001), with no evidence of physiological or clinical benefit, and the independent data and safety monitoring board recommended termination of that arm. The trial continued as a two-group study without other changes: 133 on acetylcysteine and 131 on placebo. At 60 weeks the change in forced vital capacity was -0.18 L against -0.19 L (p=0.77), with no significant difference in death (4.9% against 2.5%, p=0.30) or acute exacerbation (2.3% in each group). A regimen used as standard of care for years turned out to be actively harmful in two of its three components, and the third did nothing.
Written into the record, not signed off as a reviewed claim
Fifteen years of protecting kidneys, and then a definitive negative trial
In plain words
Acetylcysteine was given routinely before contrast scans to protect the kidneys. A trial of over five thousand high-risk patients found no difference in death, dialysis or kidney function at ninety days.
What was measured
Composite of death, dialysis or persistent 50% creatinine rise at 90 days, and contrast-associated acute kidney injury
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
PRESERVE randomised 5,177 patients at high risk of renal complications scheduled for angiography, in a two-by-two factorial design, to intravenous sodium bicarbonate or sodium chloride and to five days of oral acetylcysteine or placebo; 4,993 were in the modified intention-to-treat analysis. The sponsor stopped the trial after a prespecified interim analysis. The primary composite of death, need for dialysis, or a persistent 50% or greater rise in serum creatinine at 90 days occurred in 114 of 2,495 (4.6%) on acetylcysteine against 112 of 2,498 (4.5%) on placebo, odds ratio 1.02 (95% CI 0.78 to 1.33, p=0.88). There were no significant between-group differences in contrast-associated acute kidney injury either. The authors noted in their own background that both interventions were already widely used without definitive evidence of efficacy. This is the same failure mode as the COPD and fibrosis results: a plausible antioxidant mechanism, a surrogate endpoint that moved in small early studies, wide adoption, and a null result when a properly powered trial measured what patients care about.
Written into the record, not signed off as a reviewed claim
The mucolytic indication is a 1963 list, and the drug can close the airway it treats
In plain words
The list of conditions it is indicated for includes tuberculosis, lung amyloidosis and diagnostic bronchograms. The label also states that inhaling it unpredictably causes airway narrowing in some patients, that you cannot tell in advance who they are, and that tolerating it once does not mean tolerating it again.
What was measured
Scope of the mucolytic indication list and the label’s own account of unpredictable bronchospasm in the indicated population
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The mucolytic indication reads as adjuvant therapy for abnormal, viscid or inspissated mucous secretions in chronic emphysema, emphysema with bronchitis, chronic asthmatic bronchitis, tuberculosis, bronchiectasis, primary amyloidosis of the lung, pneumonia, bronchitis, tracheobronchitis, pulmonary complications of cystic fibrosis, tracheostomy care, pulmonary complications associated with surgery, use during anaesthesia, post-traumatic chest conditions, atelectasis due to mucous obstruction, and diagnostic bronchial studies including bronchograms, bronchospirometry and bronchial wedge catheterisation. None of that list is supported by outcome trials; it is a 1963 indication set that predates the modern efficacy standard. The mechanism paragraph hedges — the sulfhydryl group "probably" opens disulfide linkages. And the same section carries an unusually candid safety statement: patients exposed to inhaled acetylcysteine aerosol occasionally respond with increased airways obstruction of varying and unpredictable severity; those who are reactors cannot be identified a priori from a random patient population; previous reactors may not react next time and previously untroubled patients may react. The population indicated for the drug is, by definition, people with airway disease.
Source
Acetylcysteine solution United States prescribing information, Indications and Usage, Clinical Pharmacology, Warnings and Adverse Reactions
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
How many documents were read
20 documents were read for this substance.
RNAWiki source record
13 of them state the same halfLife, and they agree.
RNAWiki source record
Where else this substance is registered
FDA substance identifier (UNII)
WYQ7N0BPYC
RxNorm concept
465377
Checks this page had to pass
✓ Passed
Identity resolved
no open identity hold
✓ Passed
No unresolved merge across substance families
no quarantine open
✓ Passed
Every public sentence names a source
The opening statement carries the origin: Written into the record, not signed off.
✗ Not passed
Trial roles classified for highlighted evidence
No registered study is classified as testing this substance.
✓ Passed
No internal keys in reader text
enforced by the copy-contract test over the rendered page
✗ Not passed
Safety mode resolved
No register row and no identity class settled the question.
✓ Passed
Canonical metadata present
slug and display name present
What is missing or unclear◇Read from sources, not yet reviewed
How this medicine reached us
Kept near the foot of the page. A historical event moves up only when it changes something about this substance today.
What the approval register records
34 approved applications cover products containing this substance. The earliest was NDA013601, approved 19630914 to APOTHECON.
This order is fixed in code and does not count clicks or time on the page.
What is not here
3 questions this page could not answer
These sections were prepared and left out because there was nothing to put in them. They are listed rather than hidden, so the gaps in this record are visible.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — found nothing in the sources checked.
What changed on this page — found nothing in the sources checked.
The record as stored
The full record, for auditing
Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.
The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
A thiol that prevented hepatotoxicity in all but 6.1% of at-risk patients treated within 10 hours of a paracetamol overdose across 2,540 cases, and whose antioxidant hypothesis has since failed on hard endpoints in three separate randomised trials — no change in COPD lung-function decline or exacerbations over three years, no change in vital capacity in pulmonary fibrosis, and no change in kidney outcomes after angiography in 4,993 patients.
Recorded evidence blocks (16)
Q1
What did Acetylcysteine's largest trial (5177 people) and its longest (14 years) measure?
5177 people in Acetylcysteine's largest registered study, 14 years in its longest registered window, measuring composite of mortality and severe short term neonatal morbidities (IVH, NEC, BPD, ROP, sepsis, newborn death). ClinicalTrials.gov · 2026-09-01
139 phase2, 69 na, 69 phase3, 62 phase4, 60 phase1, 24 early phase1, 1 na or unstated; NCT01878669; 2026-12. Last human test completed 2026, NCT04300920.
Interpretation These counts include studies where Acetylcysteine was a comparison treatment, a background treatment or an exposure in an observational study, and the longest window may be a planned end date. Trial roles have not yet been classified for this record.
Show the evidence
phase2
139
na
69
phase3
69
phase4
62
phase1
60
early phase1
24
2 more recorded rows
na or unstated
1
Last recorded human testNCT04300920
2026-03-02
recorded 2026-09-01 · last checked 2026-09-04
Q2
From C. elegans to human: where has Acetylcysteine shown lifespan?
Interpretation composite of mortality and severe short term neonatal morbidities (IVH, NEC, BPD, ROP, sepsis, newborn death) — the recorded outcome words.
Show the evidence
C. elegans
lifespan
Drosophila
mechanism-only
mouse
mechanism-only
humanNCT00397735
lifespan; composite of mortality and severe short term neonatal morbidities (IVH, NEC, BPD, ROP, sepsis, newborn death); 379
recorded 2026-09-01 · last checked 2026-09-04
Q3
44 of Acetylcysteine's trials stopped: futility/efficacy, accrual/recruitment, funding/business, other?
futility/efficacy (1), accrual/recruitment (19), funding/business (6) and other (18): Acetylcysteine's stop wording, clustered. ClinicalTrials.gov · 2026-09-01
"OHSU IRB closed study to further enrollment 2/17/2006"; 44 of 379 registered studies
Show the evidence
Trial
NCT00238173
terminated; "OHSU IRB closed study to further enrollment 2/17/2006"
NCT00467831
terminated; "insufficient enrollment"
NCT00493610
suspended; "Collaborator no longer interested, short of funds"
NCT00539188
terminated; "Study terminated due to poor subject compliance."
NCT00539513
terminated; "Researchers terminated study due to limited enrollment."
NCT00569465
terminated; "End of the study"
14 further recorded trials
NCT00575419
terminated; "Low accrual"
NCT00579995
terminated; "Technical measurement problems led to unreliable or uninterpretable data."
NCT00637624
terminated; "Unable to recruit enough patients"
NCT00896025
terminated; "This observational study was stopped after 140 patients were enrolled, no more funds available to continue."
NCT00996424
terminated; "Insufficient recruitment."
NCT01138137
withdrawn; "No funding was available for the cost of the IV N-acetylcysteine (NAC)."
NCT01424033
terminated; "Departure of study team"
NCT01664260
withdrawn; "The research project has been cancelled before any participants were enrolled."
NCT01726465
terminated; "The first phase was completed"
NCT01739790
terminated; "PI discretion"
NCT01905696
terminated; "Lack of funding"
NCT02054949
withdrawn; "no eligible subjects located"
NCT02335060
terminated; "Feasibility pilot was completed"
NCT02569957
terminated; "The trial was halted prematurely due to slow accrual."
recorded 2026-09-01 · last checked 2026-09-04
Q4
Human studies of Acetylcysteine used Fluimucil (R) 600 mg, tablets — over how long?
11 recorded entries; human; tablet; also "N Acetyl cysteine, 1200mg (high dose)", "N-acetylcysteine 500 mg", "N-acetylcysteine 1000 mg"
Show the evidence
human
NCT01082445
Fluimucil (R) 600 mg, tablets
NCT01251315
N Acetyl cysteine, 1200mg (high dose)
NCT01653171
N-acetylcysteine 500 mg
NCT01653171
N-acetylcysteine 1000 mg
NCT02124525
N-acetylcysteine 3000mg a day for 12 weeks
NCT02159196
3 mL fluimucil 100mg/ml
5 more recorded rows
humanNCT02159196
3 mL-solution of acetylcysteine (fluimucil 100mg/ml)
humanNCT02252341
N-acetyl-cysteine 1800 mg a day for 12 weeks or
humanNCT03843541
N-acetylcysteine (NAC) 600 mg
humanNCT04904952
tablet; N-acetylcysteine tablet 600mg
humanNCT05951712
N Acetyl cysteine 600mg
recorded 2026-09-01 · last checked 2026-09-04
Q5
More Acetylcysteine was worse in human: at what point?
Hormetic in human: "Hormetic dose responses were commonly reported in this model, encompassing a broad range of chemicals, including principally pharmaceuticals (e.g., metformin and artemisinin), dietary supplements/extracts from medicinal plants (e.g., berberine, N-acetyl-L-cysteine, and ginsenoside Rg1) and endogenous agents (e.g.,…" Europe PMC · dose-response search · 2021-12-08
1 recorded sentence naming Acetylcysteine; Hormetic
Show the evidence
HormeticPMID 34890824
"Hormetic dose responses were commonly reported in this model, encompassing a broad range of chemicals, including principally pharmaceuticals (e.g., metformin and artemisinin), dietary supplements/extracts from medicinal plants (e.g., berberine, N-acetyl-L-cysteine, and ginsenoside Rg1) and endogenous agents (e.g., ATP, TNF-α)."
recorded 2021-12-08 · last checked 2026-09-04
Q6
Acetylcysteine's half-life is 5.6 hours — which schedules were studied?
5.6 hours, the half-life Acetylcysteine's label states. openfda-label · 5558a5f5-e821-473b-7d8a-5d33d09f0586 · 2026-08-30
Show the evidence
half life
5.6 hours hours; Elimination: After a single intravenous dose of acetylcysteine, the plasma concentration of total acetylcysteine declined in a poly-exponential decay manner with a mean terminal half-life (T 1/2 ) of 5.6 hours.
metabolism
A small fraction of an ingested dose is metabolized in the liver by the cytochrome P-450 mixed function oxidase enzyme system to form a reactive, potentially toxic, intermediate metabolite which preferentially conjugates with hepatic glutathione to form the nontoxic cysteine and mercapturic acid derivatives which are then excreted by the kidney.
recorded 2026-08-30 · last checked 2026-09-04
Q7
Could one person measure Acetylcysteine's effect on overall survival rate?
Overall survival rate: measured in Acetylcysteine's trials.
Interpretation overall survival rate is the recorded endpoint.
Show the evidence
biomarkers
overall survival rate; 2026-09-01
prevention of pulmonary mucus obstruction; 2026-09-01
exacerbations of copd condition specific quality of life; 2026-09-01
survival; 2026-09-01
endothelial function; 2026-09-01
incidence of acute renal failure; 2026-09-01
14 more recorded rows
biomarkers
clinical global impression severity; 2026-09-01
biomarkers
clinical global impression improvement; 2026-09-01
biomarkers
survival at 2 years; 2026-09-01
biomarkers
development of contrast induced nephropathy; 2026-09-01
0; NCT01138137; PHASE1; the smallest recorded human enrolment at or below 30; the registry states no direction of its result; WITHDRAWN
Q8
Which of alcohol consumption, arterial blood pressure decrease and brachial artery flow mediated dilation did Acetylcysteine's trials measure?
alcohol consumption, arterial blood pressure decrease and brachial artery flow mediated dilation lead 40 outcome terms across Acetylcysteine's trials. ClinicalTrials.gov · 2026-09-01
survival, endothelial function, incidence of acute renal failure, clinical global impression severity, clinical global impression improvement and survival at 2 years follow.
Show the evidence
overall survival rate
1
prevention of pulmonary mucus obstruction
1
exacerbations of copd condition specific quality of life
1
survival
1
endothelial function
1
incidence of acute renal failure
1
14 more recorded rows
clinical global impression severity
1
clinical global impression improvement
1
survival at 2 years
1
development of contrast induced nephropathy
1
hearing thresholds
1
proteinuria
1
alcohol consumption
1
arterial blood pressure decrease
1
post operative plasma il 6
1
nac terminal elimination half life
1
nac volume of distribution
1
nac total body clearance
1
nac concentrations
1
placental transfer
1
recorded 2026-09-01 · last checked 2026-09-04
Q9
Which of Acetylcysteine's 45 ongoing trials reports first?
"Treatment of Systemic Lupus Erythematosus (SLE) With N-acetylcysteine"; n 290; "Therapeutic benefit"; 2028-09-30
NCT01878669
"Effects of N-acetyl Cysteine During Percutaneous Coronary Intervention"; n 390; "periprocedural myocardial infarction"; 2026-12
NCT02750319
"Amiodarone and N-Acetylcysteine or Amiodarone Alone for Preventing Atrial Fibrillation After Thoracic Surgery"; n 184; "rate of sustained (lasting >30 seconds) or clinically significant post-operative atrial fibrillation (POAF)"; 2027-04
NCT03032601
"Physiological Effects of N-Acetyl Cysteine in Patients With Multiple Sclerosis"; n 55; "Changes in the metabolic activity in the brain, and improved parameters with regard to the inflammation associated with the active lesions based on both MRI and PET findings."; 2027-07-08
NCT03241732
"PET-MRI in Chronic Traumatic Brain Injury (CTBI)"; n 150; "Fluorodeoxyglucose positron emission tomography (FDG-PET)."; 2027-07-08
NCT03493178
"Glutathione in Mild Cognitive Impairment"; n 60; "Cognition"; 2026-12-31
14 further recorded trials
NCT03652753
"Pilon Fracture With Intra-articular Injection of N-Acetylcysteine (Pilon NAC)"; n 30; "Cartilage Cell Viability"; 2026-12
NCT04278898
"Targeting the Neurobiology of RRB in Autism Using N-acetylcysteine: Single-dose"; n 24; "Change in glutamatergic neurometabolites (Glx) measured by proton spectroscopy Magnetic Resonance Imaging (MRI)"; 2029-01-31
NCT04374461
"A Study of N-acetylcysteine in Patients With COVID-19 Infection"; n 48; "Arm A: number of patients who are successfully extubated and/or transferred out of critical care due to clinical improvement"; 2027-05
NCT04381897
"Use of N-Acetylcysteine in the Treatment of Repetitive and Self-Injurious Behaviors in Cornelia de Lange Syndrome"; n 10; "Change in Children's Yale-Brown Obsessive Compulsive Scale Modified for Pervasive Developmental Disorders (CYBOCS-PDD) repetitive behaviors measure score"; 2027-05-01
NCT04440280
"Targeting Reactive Oxygen Species Production as a Novel Therapeutic in Fuch's Endothelial Corneal Dystrophy"; n 45; "Level of H2O2 in the aqueous humor"; 2027-04-30
NCT04459052
"FDOPA PET and Nutritional Support in Parkinson's Disease"; n 50; "FDOPA PET"; 2027-01-08
NCT04460521
"The ACTS Trial: N-acetylcysteine (NAC) and Night-splinting as a Non-operative Treatment for Carpal Tunnel Syndrome"; n 240; "Change from baseline Boston Carpal Tunnel Questionnaire (BCTQ) at 8 weeks"; 2026-10-01
NCT04520139
"Effect of NAC on Preventing Chemo-Related Cognitive Impairments in Ovarian Ca Pts Treated W/ PBT"; n 102; "Maximum Tolerated Dose of N-Acetyl-Cysteine in Ovarian Cancer Patients Receiving Platinum-Based Therapy"; 2027-12
NCT04740580
"Glutathione, Brain Metabolism and Inflammation in Alzheimer's Disease"; n 52; "Cognition"; 2026-12-31
NCT04987775
"GWICTIC: NAC Mechanistic Study in Gulf War Veterans"; n 170; "Assess glutathione levels"; 2026-04
NCT05081479
"A Study of N-Acetylcysteine (N-AC) in People Receiving CAR T-cell Therapy for Lymphoma"; n 9; "Maximum tolerated dose of N-AC"; 2026-10-21
NCT05122559
"Neuroprotection With N-acetyl Cysteine for Patients With Progressive Multiple Sclerosis"; n 98; "Safety and tolerability"; 2027-02
NCT05123365
"An Optimal Dose Finding Study of N-Acetylcysteine in Patients With Myeloproliferative Neoplasms"; n 27; "Optimal Biological Dose (OBD) of N-Acetylcysteine"; 2026-11-15
NCT05142735
"Effects of NAC on Symptoms of CHR Patients"; n 90; "Change in positive psychosis-like symptoms from baseline to 8 weeks"; 2026-12-31
recorded 2026-09-01 · last checked 2026-09-04
Q10
Which running trial of Acetylcysteine could settle lifespan?
NCT07765823 measures Survival/Mortality rate, reading out 2026-10-17.
3 open trials; n 62; "Role of N-Acetylcysteine in Non-Acetaminophen-Induced Liver Failure"
Show the evidence
Trial
NCT07765823
"Role of N-Acetylcysteine in Non-Acetaminophen-Induced Liver Failure"; n 62; "Survival/Mortality rate"; 2026-10-17
NCT05294744
"Utility of the Use of N-acetylcysteine Associated With Conventional Treatment in Patients With Severe Acute Alcoholic Hepatitis (Maddrey> 32)"; n 390; "Number of Participants with all-cause mortality at 6 months."; 2026-12
NCT03032601
"Physiological Effects of N-Acetyl Cysteine in Patients With Multiple Sclerosis"; n 55; "Changes in the metabolic activity in the brain, and improved parameters with regard to the inflammation associated with the active lesions based on both MRI and PET findings."; 2027-07-08
Q11
Which 127 trials of Acetylcysteine posted no result?
Posted no result
127 of 127 completed trials
Registrations
NCT00184977, NCT00003346, NCT00639496, NCT00492518, NCT00830193 and NCT00136825, and 121 more
Completion dates
oldest 2003-01; newest 2024-08-31
Show the evidence
Trial
NCT00184977
2003-01
NCT00003346
2003-02
NCT00639496
2003-07
NCT00492518
2004-10
NCT00830193
2005-05
NCT00136825
2005-09
14 further recorded trials
NCT00463671
2005-09
NCT00122018
2006-03
NCT00332631
2006-03
NCT00273702
2006-09
NCT01506765
2006-09
NCT00808795
2006-10
NCT00004467
2006-11
NCT00211653
2006-11
NCT00196885
2006-12
NCT00556465
2007-06
NCT00188630
2007-07
NCT00751257
2007-10
NCT00131521
2007-12
NCT00493727
2007-12
Q12
At the median, Acetylcysteine's trials enrolled 52 people — anything larger?
Median enrolment
52
Largest enrolment
5177
Registered trials counted
372
Q13
What do 594 spontaneous reports say about Acetylcysteine — and not say?
These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.
Acetylcysteine appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 594 reaction mentions were counted: acute kidney injury 149; dyspnoea 92; pruritus 62; stevens-johnson syndrome 57. open-targets-adr · CHEMBL600 · 2026-06-24
Show the evidence
acute kidney injury
149
dyspnoea
92
pruritus
62
stevens-johnson syndrome
57
toxicity to various agents
46
nephropathy toxic
45
4 more recorded rows
erythema
42
urticaria
42
anaphylactoid reaction
30
asthma
29
recorded 2026-06-24 · last checked 2026-09-04
Q14
Acetylcysteine and CYP2E1: shared by which compounds?
CYP2E1 appear in Acetylcysteine's recorded interaction sentences, 1 in all. openfda-label+europepmc · 2026-08-30
Interpretation clinical_pharmacology
Show the evidence
CYP2E1clinical_pharmacology
A small fraction of an ingested dose is metabolized in the liver by isozyme CYP2E1 of the cytochrome P-450 mixed function oxidase enzyme system to form a reactive, potentially toxic, intermediate metabolite.
recorded 2026-08-30 · last checked 2026-09-04
Q15
Was Acetylcysteine studied with exercise?
exercise is named in Acetylcysteine's label sentences: "METHODS: n this 24-week randomized, double-blind, placebo-controlled trial, participants enrolled in an exercise-based cardiac rehabilitation program with possible vascular mild cognitive impairment were randomized to receive either oral N-acetylcysteine (2400 mg/day) or placebo." openfda-label+europepmc · 2026-08-30
1 recorded statement; exercise
Show the evidence
exercise
METHODS: n this 24-week randomized, double-blind, placebo-controlled trial, participants enrolled in an exercise-based cardiac rehabilitation program with possible vascular mild cognitive impairment were randomized to receive either oral N-acetylcysteine (2400 mg/day) or placebo.
recorded 2026-08-30 · last checked 2026-09-04
Q16
What is recorded about Acetylcysteine and autophagy?
"After N-acetyl-L-cysteine (NAC)-mediated inhibition of ROS, autophagy levels and IVM resistance in the resistant strain were substantially reduced." — where Acetylcysteine and autophagy appear together. Europe PMC · pathway abstract search · 2026-08-19
"After N-acetyl-L-cysteine (NAC)-mediated inhibition of ROS, autophagy levels and IVM resistance in the resistant strain were substantially reduced."
PMID 42314534
"Furthermore, the mechanisms were investigated using the autophagy inhibitor hydroxychloroquine (HCQ), ROS scavenger N-acetylcysteine (NAC), and PI3K/AKT pathway activator Recilisib."
mTORPMID 42196610
"Inhibition of autophagy with <i>N</i>-acetylcysteine and 3-methyladenine partially rescued cell viability, restored p-Akt levels, and reduced LC3-II, indicating that cell death is regulated via the ROS-mediated Akt/mTOR signaling axis."
autophagyPMID 42196610
"Inhibition of autophagy with <i>N</i>-acetylcysteine and 3-methyladenine partially rescued cell viability, restored p-Akt levels, and reduced LC3-II, indicating that cell death is regulated via the ROS-mediated Akt/mTOR signaling axis."
mTORPMID 41300463
"To examine these effects, MLO-Y4 cells and primary mouse osteocytes were cultured under normal glucose and HG conditions, with additional treatments using N-acetylcysteine (NAC, ROS scavenger) and rapamycin (autophagy promoter and mTOR inhibitor)."
AMPKPMID 39218924
"Based on this, we subsequently modeled pyroptosis using lipopolysaccharides and nigericin sodium salt, then autophagy inhibitors chloroquine (CQ), AMP-activated protein kinase (AMPK) inhibitors compound C (CC) and reactive oxygen species (ROS) scavengers N-acetyl-L-cysteine (NAC) were further used to examine the expression of proteins related to pyroptosis, autophagy and AMPK pathway in…"
senolyticPMID 42688195
"Building on those directional findings, this short communication proposes a minimal three-arm oral regimen with unequal evidentiary weight: first, the Cheung Glutamatergic Regimen, consisting of low-dose dextromethorphan potentiated by a CYP2D6 inhibitor together with piracetam and L-glutamine, as an exploratory adjunct aimed at preserving residual functional connectivity; second, daily…"
NAD+PMID 42688195
"Building on those directional findings, this short communication proposes a minimal three-arm oral regimen with unequal evidentiary weight: first, the Cheung Glutamatergic Regimen, consisting of low-dose dextromethorphan potentiated by a CYP2D6 inhibitor together with piracetam and L-glutamine, as an exploratory adjunct aimed at preserving residual functional connectivity; second, daily…"
2 more recorded rows
AMPKPMID 42290138
"Our results indicate that mitophagy promoted by MT is essential to deactivate NLRP3 inflammasome and alleviate the development of arthritis, which provides a candidate for the treatment of RA.<b>Abbreviations:</b> 3-MA: 3-methyladenine; ACP5/TRAP: acid phosphatase 5, tartrate resistant; ANOVA: analysis of variance; ATG5: autophagy releated 5; ATP: adenosine triphosphate; BMD: bone mineral…"
sirtuinPMID 37059380
"The results showed that DBP caused mitochondrial damage, autophagy, apoptosis and necroptosis; Transcriptomics analysis identified that MAPK and PI3K were significant factors in the cytotoxic changes induced by DBP; N-Acetyl-L-cysteine (NAC), SIRT1 activator, ERK inhibitor, p38 inhibitor and ERK siRNA treatments counteracted the changes of SIRT1/PGC-1α and Nrf2 pathway-related proteins, autophagy…"
recorded 2026-08-19 · last checked 2026-09-04
Where it is registeredIdentifiers, relations and other names
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