This page shows what was measured, who it was measured in, and what that does not settle.
What Salbutamol does in the body
A sudden tight chest and wheeze — the blue rescue inhaler
A band of muscle wraps around each airway. Albuterol lands on a receptor on the outside of those muscle cells and switches on a signal that lowers the calcium inside them, so the muscle cannot stay contracted and the airway springs open. It works whatever caused the squeeze, which is why it helps in cold air, exercise and allergy alike. It does nothing to the swelling and mucus underneath, and after about four hours it has washed out and the airway is exactly as inflamed as it was.
What happened in people
Mean onset of a 15% FEV1 rise at 5.4 minutes, peak at 56 minutes and duration of about 4 hours in responders, across two 12-week placebo-controlled trials in 610 patients
✎ 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.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · a recorded source, not a stored snapshot
The nebuliser solution costs about twenty-five United States cents a millilitre at pharmacy acquisition cost; the device, not the drug, is the expense
Where it acts
Beta-2 adrenergic receptors on the smooth muscle ring around the airways, from the trachea to the terminal bronchioles
Kind of result
The kind of result is not recorded
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.
Where each sentence above came from
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 131 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.
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.
Absolute difference
An absolute difference is how many more people in a hundred were affected.
A picture of it, and where the picture fails
It is like counting heads in two rooms of a hundred.
Where that stops being true. Heads are easy to count. Study results carry a margin of error too.
What people get wrong. It is confused with a percentage change, which can look far larger.
The arithmetic difference in event rates between arms.
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.
Formulation
A formulation is the exact made-up form a substance comes in.
A picture of it, and where the picture fails
It is like the difference between a whole bean and instant coffee.
Where that stops being true. Coffee tastes different. A formulation can change how much reaches the blood.
What people get wrong. Two products with the same name are assumed to behave the same. They often do not.
The specific composition and physical form of a product, including salt, excipients and release profile.
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.
Serial FEV1 as percentage change from test-day baseline over 12 weeks in subjects aged 12 and over with mild to moderate asthma
✓ The study showed what it set out to show
Who was studied
Two 12-week placebo-controlled registration trials (NDA 020983)
Significantly greater improvement in FEV1 than placebo at day 1 (n=297) and at week 12 (n=249); in responders, mean onset 5.4 minutes, mean time to peak 56 minutes, mean duration approximately 4 hours
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. These are lung-function trials. No exacerbation, hospitalisation or mortality endpoint was measured in them, which is why the effect on the outcomes people care about had to come from other trials entirely.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Pressurised metered-dose inhaler delivering 90 mcg of albuterol base per actuation; also nebuliser solution, dry-powder inhaler, oral tablets and syrup
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · a recorded source, not a stored snapshot
Morning peak expiratory flow after 16 weeks of regularly scheduled against as-needed inhaled albuterol in mild chronic stable asthma
✗ The study did not show it
Who was studied
ACRN regular versus as-needed albuterol (N Engl J Med 1996;335:841-847)
How many people
255
Study design
Phase 4, randomised, double-blind, multicentre
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
416 to 414 L/min scheduled against 424 to 424 L/min as needed, p=0.71; no significant difference in FEV1, symptoms, quality of life or methacholine responsiveness
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. A deliberately two-sided question. The trial was powered to detect harm from regular use as well as benefit, and found neither. It is the reason as-needed use became the standard prescription.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Pressurised metered-dose inhaler delivering 90 mcg of albuterol base per actuation; also nebuliser solution, dry-powder inhaler, oral tablets and syrup
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · a recorded source, not a stored snapshot
Morning peak expiratory flow during regularly scheduled albuterol against placebo, in patients matched on FEV1 and stratified by ADRB2 codon 16 genotype
Gly/Gly +14 L/min (95% CI 3 to 25, p=0.0175); Arg/Arg -10 L/min (95% CI -19 to -2, p=0.0209); genotype-attributable difference -24 L/min (95% CI -37 to -12, p=0.0003)
Repeated elsewhere
Partially 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. Thirty-seven Arg/Arg and 41 Gly/Gly patients is a small trial for a pharmacogenetic claim, and four of 41 matched pairs withdrew before randomisation. The result has not translated into genotype-directed prescribing or into the label.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Pressurised metered-dose inhaler delivering 90 mcg of albuterol base per actuation; also nebuliser solution, dry-powder inhaler, oral tablets and syrup
Interval reported. 95% CI 3 to 25, p=0
Written into the record, not signed off as a reviewed claim.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · a recorded source, not a stored snapshot
Electronically recorded percentage of weeks with well-controlled asthma, as-needed budesonide-formoterol against as-needed terbutaline in mild asthma
✓ The study showed what it set out to show
Who was studied
SYGMA 1 (NCT02149199)
How many people
3836
Study design
Phase 3, randomised, double-blind, 52 weeks
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
34.4% against 31.1% of weeks well controlled, odds ratio 1.14 (95% CI 1.00 to 1.30), p=0.046
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. The primary endpoint barely moved; the secondary endpoint moved a great deal. Annual severe exacerbations were 0.20 on the short-acting agonist alone against 0.07 on the steroid-containing reliever, rate ratio 0.36 (95% CI 0.27 to 0.49). A trial can be won on a symptom score and be important for something else.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Pressurised metered-dose inhaler delivering 90 mcg of albuterol base per actuation; also nebuliser solution, dry-powder inhaler, oral tablets and syrup
Interval reported. 95% CI 1
Written into the record, not signed off as a reviewed claim.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · 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 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.
Where a source records it acting
Lungs and airways: Relaxes the smooth muscles of all airways, from the trachea to the terminal bronchioles
US prescribing information · 04c8a345-0a0d-5a01-e063-6294a90a40d2 · read 2026-08-27
Start
Salbutamol
What a person takes: Pressurised metered-dose inhaler delivering 90 mcg of albuterol base per actuation; also nebuliser solution, dry-powder inhaler, oral tablets and syrup.
The measurement behind this step
The inhaled route exists to put a systemically active sympathomimetic where it is needed and nowhere else. Systemic levels after recommended inhaled doses are low. The canister is a microcrystalline suspension of albuterol sulfate in HFA-134a propellant with no other excipient, and must be primed with four sprays before first use, after a drop, or after more than two weeks unused. Oral formulations reach the same receptors by the same mechanism with far more tremor and tachycardia for the same bronchodilation.
Getting in
A cloud of drug, most of which never reaches the lung
One press releases a measured puff. Some of it lands in the mouth and throat and is swallowed; the fraction that reaches the airways is what does the work.
──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
Each actuation delivers 120 mcg of albuterol sulfate from the valve, 108 mcg from the mouthpiece, equivalent to 90 mcg of albuterol base. Systemic levels after recommended doses are low; a supratherapeutic 1,080 mcg dose in 12 healthy subjects gave mean peak plasma concentrations of about 3 ng/mL. Tmax was 0.42 hours with the HFA-134a propellant against 0.17 hours with the older CFC formulation.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · a recorded source, not a stored snapshot
The target sits on the outside surface of the muscle cell. Albuterol docks there from the airway side and the entire signal is passed inwards by the receptor.
╌╌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 beta-2 adrenergic receptor is a seven-transmembrane G-protein-coupled receptor. Albuterol is a hydrophilic saligenin: the catechol ring of adrenaline is replaced by a 4-hydroxy-3-hydroxymethylphenyl group, which resists catechol-O-methyltransferase and keeps the molecule at the extracellular surface rather than in the membrane, giving a fast onset and a short duration.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · a recorded source, not a stored snapshot
The receptor is switched on, in the lung and a little in the heart
The airway receptor is the intended one. The same receptor exists on the heart, which is why a rescue inhaler can make the pulse race and the hands shake.
──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
Preferential rather than absolute beta-2 selectivity. The label records that beta-2 adrenoceptors constitute 10% to 50% of total beta-adrenoceptors in the human heart, that their function has not been established, and that their presence raises the possibility of cardiac effects even from selective agonists. Reported electrocardiogram changes include T wave flattening, QTc prolongation and ST segment depression, of unknown clinical relevance.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · a recorded source, not a stored snapshot
The switched-on receptor raises a second messenger inside the cell, which strips calcium away from the contraction machinery. The muscle band releases.
╌╌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
Receptor occupancy activates adenylyl cyclase, raising intracellular cyclic AMP; cyclic AMP activates protein kinase A, which inhibits phosphorylation of myosin and lowers intracellular ionic calcium, producing relaxation. Because the step is downstream of the receptors that constrict, albuterol acts as a functional antagonist and relaxes the airway irrespective of the spasmogen involved. Raised cyclic AMP also inhibits mediator release from airway mast cells.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · a recorded source, not a stored snapshot
The airway opens in minutes and closes again in hours
FEV1 starts rising within six minutes, peaks at about an hour, and is back to baseline in roughly four.
──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
In responders in the registration trials, mean time to a 15% FEV1 increase was 5.4 minutes, mean time to peak effect 56 minutes, and mean duration approximately 4 hours, up to 6 hours in some subjects. Apparent terminal plasma half-life is about 4.6 hours.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · a recorded source, not a stored snapshot
Nothing in this sequence reduces the swelling or the mucus. That is why needing the inhaler more often is a signal rather than a solution.
──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
Label section 5.3 states that beta-adrenergic agonist bronchodilators used alone may not be adequate to control asthma in many patients, and directs early consideration of anti-inflammatory agents. Section 5.2 states that needing more doses than usual may be a marker of destabilisation requiring reassessment. In SYGMA 1 the severe exacerbation rate on a short-acting agonist alone was 0.20 per year against 0.07 when an inhaled steroid was carried in the reliever.
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · 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 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 with asthma, chronic obstructive pulmonary disease and other reversible airway narrowing, aged 4 and over for the metered-dose inhaler. Three trials in children under 4 did not establish efficacy in that age group.
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: “The safety and effectiveness of Albuterol Sulfate HFA Inhalation Aerosol for treatment of exercise-induced bronchospasm in children 12 years of age and older is based on one single-dose crossover study in 24 adults and adolescents with exercise-induced bronchospasm comparing doses of 180 mcg with placebo [see Clinical Studies (14.2) ].”
US prescribing information · 8c278b6f-d32b-b750-e053-2995a90ad7e9 · read 2026-08-30
On older people, the label states: “Clinical studies of Albuterol Sulfate HFA Inhalation Aerosol did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently from younger patients.”
US prescribing information · 8c278b6f-d32b-b750-e053-2995a90ad7e9 · read 2026-08-30
On people who are pregnant, the label states: “Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to asthma medications during pregnancy.”
US prescribing information · 8c278b6f-d32b-b750-e053-2995a90ad7e9 · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary There are no available data on the presence of albuterol in human milk, the effects on the breastfed child, or the effects on milk production.”
US prescribing information · 8c278b6f-d32b-b750-e053-2995a90ad7e9 · read 2026-08-30
Where the result stopped carrying
Regularly scheduled dosing produced no benefit at all over as-needed dosing in mild asthma
In Arg/Arg homozygotes, regularly scheduled dosing produced worse morning peak flow than placebo
Three trials in children from birth to 4 years failed to establish efficacy, and the label says so
The 2014 American paediatric guideline issued a strong recommendation against using it in bronchiolitis, reversing the 2006 position
Paradoxical bronchospasm, which may be life threatening, occurs with an inhaled bronchodilator and most often with the first use of a new canister
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 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.
A different form was studied
The studied form is not the form on the shelf.
On this record: This record is linked to 1 related forms. Evidence does not carry across all of them.
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)
It was studied for a different goal
The studies measured something else entirely. 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
Prescription only
❝ 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
Pressurised metered-dose inhaler delivering 90 mcg of albuterol base per actuation; also nebuliser solution, dry-powder inhaler, oral tablets and syrup
✎ 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
The inhaled route exists to put a systemically active sympathomimetic where it is needed and nowhere else. Systemic levels after recommended inhaled doses are low.
✎ 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. The rest of the recorded wording: The canister is a microcrystalline suspension of albuterol sulfate in HFA-134a propellant with no other excipient, and must be primed with four sprays before first use, after a drop, or after more than two weeks unused. Oral formulations reach the same receptors by the same mechanism with far more tremor and tachycardia for the same bronchodilation.
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 hypersensitivity to an ingredient. Paradoxical bronchospasm may be life threatening and most often follows the first use of a new canister; the label directs immediate discontinuation. Fatalities have been reported with excessive use of inhaled sympathomimetics. Cardiovascular effects include pulse and blood pressure change and electrocardiogram changes of unknown clinical relevance. Significant hypokalaemia may occur through intracellular shunting, usually transient. Caution in convulsive disorders, hyperthyroidism and diabetes; large intravenous doses have aggravated pre-existing diabetes and ketoacidosis. Adverse reactions at 3% or more in trials were throat irritation, viral respiratory infections, upper respiratory inflammation, cough and musculoskeletal pain.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Where this came from
VENTOLIN HFA (albuterol sulfate) inhalation aerosol United States prescribing information — Indications 1.1 and 1.2, Contraindications 4, Warnings 5.1 to 5.8… · 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
Pressurised metered-dose inhaler delivering 90 mcg of albuterol base per actuation; also nebuliser solution, dry-powder inhaler, oral tablets and syrup
✎ 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
Systemic levels after recommended inhaled doses are low.
✎ 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. The rest of the recorded wording: The canister is a microcrystalline suspension of albuterol sulfate in HFA-134a propellant with no other excipient, and must be primed with four sprays before first use, after a drop, or after more than two weeks unused. Oral formulations reach the same receptors by the same mechanism with far more tremor and tachycardia for the same bronchodilation.
No source is stored against this line.
What is recorded as being sold
175 products list this as an active ingredient in the United States drug directory. 156 of them contain it and nothing else.
FDA National Drug Code directory · 71872-7054 · read 2026-08-29
They are sold as aerosol, metered, inhalant, powder, powder, metered, solution and spray, metered, taken oral and respiratory (inhalation).
FDA National Drug Code directory · 71872-7054 · read 2026-08-29
The regulator's established pharmacologic class for it is adrenergic beta2-agonists [moa] and beta2-adrenergic agonist [epc].
FDA National Drug Code directory · 71872-7054 · read 2026-08-29
133 published labels name it as an active ingredient. 114 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 32377c09-da6d-331c-e063-6294a90a7a46 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 32377c09-da6d-331c-e063-6294a90a7a46 · read 2026-08-29
Albuterol Sulfate HFA is inhalation aerosol (pressurized metered-dose aerosol canister) at 108 mcg of albuterol sulfate (90 mcg of albuterol base) from the mouthpiece per actuation; 200 metered inhalations per canister, recorded as prescription product; fda label in effect 2024-12-31 in the United States.
US prescribing information · 04c8a345-0a0d-5a01-e063-6294a90a40d2 · read 2026-08-27
Recorded price in US: 0.28866–0.52699 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 16 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.
Evidence on this page does not automatically apply to this one.
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 Salbutamol 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 fast, reliable relief of bronchospasm amounts to control of asthma — the label itself says a beta-agonist alone may not be adequate in many patients
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 mortality gradient with rising canister counts is caused by the canisters, when the same registry cannot separate heavy use from severe undertreated disease
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 because it opens adult asthmatic airways it will open a wheezing infant’s, which the bronchiolitis evidence contradicts
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 drug behaves the same way in everyone taking it regularly, when codon 16 genotype reversed the direction of the effect
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 Salbutamol 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.
Five minutes to open, four hours to close again
In plain words
The speed is real and it was timed. In the responders in the registration trial, half the maximum effect arrived in under six minutes, the peak came at just under an hour, and it was gone in about four hours.
What was measured
Serial FEV1 as percentage change from pre-dose baseline, and time to onset, peak and offset in responders
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Efficacy was established in two 12-week randomised, double-blind, placebo-controlled trials in 610 subjects aged 12 and over with mild to moderate asthma, using serial FEV1 as percentage change from test-day baseline. Two inhalations produced significantly greater improvement in FEV1 than placebo at day 1 and again at week 12, so the effect did not wear off over the treatment period. In the responder population, defined as a 15% or greater rise in FEV1 within 30 minutes of dosing, the mean time to onset of that 15% rise was 5.4 minutes, the mean time to peak effect was 56 minutes, and the mean duration of effect was approximately 4 hours, reaching 6 hours in some subjects. A separate 2-week trial in 135 children aged 4 to 11 gave the same pattern.
Source
VENTOLIN HFA (albuterol sulfate) United States prescribing information, section 14.1 (NDA 020983)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
Using it alone stopped being a recommended way to treat asthma
In plain words
For decades mild asthma was treated with the blue inhaler and nothing else. A trial that put 1,277 people on a reliever alone and 1,277 on a reliever containing a steroid found nearly three times the severe attacks in the first group, and the guidelines changed.
What was measured
Annual rate of severe asthma exacerbations with a short-acting beta-agonist alone against an as-needed inhaled corticosteroid–formoterol reliever
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
SYGMA 1 randomised 3,836 patients aged 12 and over with mild asthma to twice-daily placebo plus as-needed terbutaline, twice-daily placebo plus as-needed budesonide-formoterol, or twice-daily budesonide plus as-needed terbutaline, for 52 weeks. The annual rate of severe exacerbations was 0.20 with the short-acting agonist alone, 0.07 with the as-needed steroid combination and 0.09 with maintenance budesonide — a rate ratio of 0.36 (95% CI 0.27 to 0.49) for the combination against the agonist alone. The symptom endpoint moved far less: 34.4% against 31.1% of weeks well controlled, odds ratio 1.14 (95% CI 1.00 to 1.30, p=0.046). The lesson is not that albuterol stopped working. It is that the thing it fixes and the thing that lands people in hospital are different, and a strategy built only on the first leaves the second untreated.
Written into the record, not signed off as a reviewed claim
Taking it on a schedule adds nothing to taking it when you need it
In plain words
Four puffs a day, every day, was tested against using the inhaler only when symptoms came. Over sixteen weeks the morning peak flow was identical, and so was everything else measured.
What was measured
Morning peak expiratory flow after 16 weeks of scheduled against as-needed albuterol
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The Asthma Clinical Research Network randomised 255 patients with mild chronic stable asthma to inhaled albuterol on a regular schedule (n=126) or as needed only (n=129) for 16 weeks, double-blind. Morning peak expiratory flow, the primary outcome, was 416 L/min after run-in and 414 L/min after treatment in the scheduled group, and 424 L/min at both times in the as-needed group (p=0.71). There were no significant differences in peak flow variability, FEV1, supplemental albuterol use, symptoms, quality of life, or methacholine responsiveness. The small differences in evening peak flow and short-term bronchodilator response were judged clinically unimportant. The authors concluded that inhaled albuterol should be prescribed on an as-needed basis — a negative result that settled a real controversy about whether regular use was actively harmful, and simultaneously removed any reason for it.
Written into the record, not signed off as a reviewed claim
In one sixth of people, regular use made lung function worse
In plain words
A single letter difference in the beta-2 receptor gene flipped the result. People with two copies of the arginine version got worse on regular albuterol; people with two copies of the glycine version got better. The gap between them was larger than the drug effect itself.
What was measured
Morning peak expiratory flow on regularly scheduled albuterol against placebo, stratified by ADRB2 codon 16 genotype
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
BARGE enrolled patients with mild asthma in pairs matched on FEV1 by genotype at residue 16 of the beta-2 adrenergic receptor: Arg/Arg (n=37) or Gly/Gly (n=41). Regularly scheduled albuterol or placebo was given in a masked crossover design for 16-week periods, with as-needed albuterol withdrawn and ipratropium substituted as the reliever. Morning peak expiratory flow was the primary outcome. Gly/Gly patients gained 14 L/min on regular albuterol against placebo (95% CI 3 to 25, p=0.0175). Arg/Arg patients lost 10 L/min (95% CI -19 to -2, p=0.0209). The genotype-attributable treatment difference was -24 L/min (95% CI -37 to -12, p=0.0003), with matching genotype-specific effects on FEV1, symptoms and reliever use. Homozygous Arg16 occurs in roughly one in six people. Nothing in the United States label mentions this, and no genotype-directed prescribing followed.
Written into the record, not signed off as a reviewed claim
It was given to wheezing infants for years and it does not work there
In plain words
Bronchiolitis in a baby looks like asthma and is not. The 2006 American paediatric guideline allowed a trial of albuterol; the 2014 revision issued a strong recommendation against giving it at all.
What was measured
Guideline recommendation strength for bronchodilators in bronchiolitis, 2006 against 2014
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The American Academy of Pediatrics clinical practice guideline on the diagnosis, management and prevention of bronchiolitis, revised in 2014 for children aged 1 through 23 months, replaced the 2006 guideline that had permitted a monitored trial of a bronchodilator. The revision states that clinicians should not administer albuterol or salbutamol to infants and children with a diagnosis of bronchiolitis, at evidence quality B and strength strong recommendation. The mechanism explains the finding: airway obstruction in bronchiolitis is sloughed epithelium, oedema and mucus plugging in airways whose smooth muscle is scant, and relaxing smooth muscle that is not the obstruction cannot help. Separately, the albuterol label records that three trials in children between birth and 4 years of age did not establish efficacy in that age group.
Written into the record, not signed off as a reviewed claim
The mortality signal is a marker as much as a cause
In plain words
People who get through many rescue inhalers a year die more often. That is solidly measured. Whether the inhalers are doing the killing, or are simply the fingerprint of asthma bad enough to kill, is not settled by the data that show it.
What was measured
That heavy rescue-inhaler use causes the excess mortality associated with it, rather than marking the severity and undertreatment that cause both
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The SABINA Swedish cohort linked national registries for 365,324 asthma patients aged 12 to 45 with a mean 85.4 months of follow-up. Thirty per cent collected three or more short-acting beta-agonist canisters a year. Against two or fewer canisters, exacerbation hazard ratios were 1.26 (95% CI 1.24 to 1.28) at 3 to 5 canisters, 1.44 (1.41 to 1.46) at 6 to 10 and 1.77 (1.72 to 1.83) at 11 or more; mortality hazard ratios across 2,564 deaths were 1.26 (1.14 to 1.39), 1.67 (1.49 to 1.87) and 2.35 (2.02 to 2.72). This is an observational cohort with confounding by indication built into it: the people using the most reliever are the people with the worst disease and, frequently, the least controller treatment. The label states directly that fatalities have been reported with excessive use of inhaled sympathomimetics and that the exact cause of death is unknown. Both statements can be true, and neither licenses the claim that reducing canister counts by itself reduces deaths.
Written into the record, not signed off as a reviewed claim
How many documents were read
113 documents were read for this substance.
RNAWiki source record
2 of them state the same proteinBinding, and they agree.
RNAWiki source record
Where else this substance is registered
FDA substance identifier (UNII)
021SEF3731
CAS registry number
18559-94-9
PubChem compound
2083
RxNorm concept
142153
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.
Withdrawn in United States, 2023, for "Defective container: empty inhaler and leakage observed through the inhaler valve due to partially missing bottom seat (gasket)." (openFDA drug enforcement Class I recall)
What the approval register records
112 approved applications cover products containing this substance. The earliest was NDA018473, approved 19810501 to GLAXOSMITHKLINE.
This order is fixed in code and does not count clicks or time on the page.
What is not here
7 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 was measured, goal by goal — found nothing in the sources checked.
How close this is to real life — found nothing in the sources checked.
Felt, measured, or meaningful — found nothing in the sources checked.
How long anything takes — found nothing in the sources checked.
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 beta-2 agonist that relaxes airway smooth muscle within a measured 5.4 minutes and holds for about four hours, and which in SYGMA 1 — where 1,277 patients used a short-acting agonist alone as their only reliever — left an annual severe exacerbation rate of 0.20 against 0.07 for an inhaled steroid combination reliever, a rate ratio of 0.36.
Recorded evidence blocks (9)
Q1
On the Salbutamol label: indicated for what?
"Albuterol Sulfate Inhalation Aerosol is a beta 2 -adrenergic agonist indicated for: Treatment or prevention of bronchospasm in patients 4 years of age and older with reversible obstructive airway disease. ( 1.1 ) Prevention of exercise-induced bronchospasm in patients 4 years of age and older.": indications and usage on Salbutamol's label. DailyMed label · 17858afa-dcdf-4612-b475-3b6baadfb639 · 2026-08-06
Q2
261 registered trials of Salbutamol — at which phases?
Registered studies posting no result
176 of 261
261 registered studies of Salbutamol: 69 phase4, 57 na, 56 phase3, 34 phase2, 27 phase1, 18 na or unstated, 4 early phase1. CLINICALTRIALS_SNAPSHOT · 2026-09-01
938 with a PubMed record
Show the evidence
phase4
69
na
57
phase3
56
phase2
34
phase1
27
na or unstated
18
9 more recorded rows
early phase1
4
completed
181
unknown
35
terminated
17
recruiting
9
withdrawn
8
active not recruiting
5
not yet recruiting
5
suspended
1
recorded 2026-09-01 · last checked 2026-09-04
Q3
23 of Salbutamol's trials stopped: safety, accrual/recruitment, funding/business, other?
safety (1), accrual/recruitment (4), funding/business (5) and other (13): Salbutamol's stop wording, clustered. CLINICALTRIALS_SNAPSHOT · 2026-09-01
"Record is an ACRN grant summary \& not reflective of an individual trial. All ACTs conducted by ACRN were individually registered on the PRS."; 23 of 261 registered studies
Show the evidence
Trial
NCT00000577
withdrawn; "Record is an ACRN grant summary \& not reflective of an individual trial. All ACTs conducted by ACRN were individually registered on the PRS."
NCT00180843
terminated; "lack of resources research fellow left"
NCT00434993
terminated; "Stopped for futility by DSMB"
NCT00634517
terminated; "IND voluntarily withdrawn, without prejudice"
NCT00634829
terminated; "IND voluntarily withdrawn, without prejudice"
NCT00635505
terminated; "IND voluntarily withdrawn, without prejudice"
14 further recorded trials
NCT00783250
terminated; "Problems with data collection"
NCT00830882
withdrawn; "Lack of funding"
NCT01375361
withdrawn; "Low enrollment."
NCT01951378
terminated; "No data are available for this study as the PI has left the institution."
NCT02108743
withdrawn; "Lack of funding"
NCT02499887
terminated; "Exclusion criteria prevented enrollment of adequate # of participants"
NCT02508311
terminated; "Our ability to test subjects with tetraplegia in this interventional study was interrupted by the COVID-19 pandemic. Our research pharmacist also informed us that oral albuterol is no longer being manufactured."
NCT02966184
terminated; "Study Drug Backorder"
NCT03098680
terminated; "Unable to recruit in time before end of PhD studentship"
NCT03199976
terminated; "Subjects in the Salbutamol group discontinued the intervention more often due to troublesome respiratory symptoms"
NCT03586544
terminated; "The study was halted prematurely due to COVID 19."
NCT03592212
terminated; "Number of inclusioNs not reached"
NCT04184609
withdrawn; "Funding ran out before participants were enrolled."
NCT04584034
withdrawn; "Premature ending of the study due to impossibility of obtaining a suitable placebo-inhaler"
recorded 2026-09-01 · last checked 2026-09-04
Q4
Human studies of Salbutamol used Salbutamol 400mcg — over how long?
Human studies of Salbutamol used "Salbutamol 400mcg". ClinicalTrials.gov · 2026-09-01
20 recorded entries; human; inhalation; also "Salbutamol 100 mcg", "Budesonide inhalation suspension (0.5 mg/2mL) 2mg, albuterol (5mg/mL) 7.5 or 10mg", "salbutamol 100 mcg"
6 hours; The terminal plasma half-life of albuterol delivered by Albuterol Sulfate Inhalation Aerosol was approximately 6 hours.
metabolismpharmacokinetics
Metabolism and Elimination: Information available in the published literature suggests that the primary enzyme responsible for the metabolism of albuterol in humans is SULTIA3 (sulfotransferase).
recorded 2026-08-06 · last checked 2026-09-04
Q6
Which 92 trials of Salbutamol posted no result?
Posted no result
92 of 92 completed trials
Registrations
NCT00004685, NCT00685126, NCT00665600, NCT00646009, NCT00646620 and NCT00027391, and 86 more
Completion dates
oldest 2000-09; newest 2024-07-15
Show the evidence
Trial
NCT00004685
2000-09
NCT00685126
2002-07
NCT00665600
2003-03
NCT00646009
2003-08
NCT00646620
2003-09
NCT00027391
2004-08
14 further recorded trials
NCT00382889
2004-09
NCT00667797
2005-05
NCT00649779
2005-10
NCT00649987
2005-10
NCT00272753
2005-11
NCT00117182
2006-08
NCT00358488
2007-01
NCT00497523
2007-01
NCT00730197
2007-03
NCT00315744
2007-04-12
NCT00549120
2007-10-26
NCT00039988
2007-11
NCT00565591
2008-02
NCT00911651
2008-08
Q7
At the median, Salbutamol's trials enrolled 62 people — anything larger?
Median enrolment
62
Largest enrolment
124117
Registered trials counted
260
Q8
What do 13731 spontaneous reports say about Salbutamol — 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.
Salbutamol appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 13731 reaction mentions were counted: asthma 3143; dyspnoea 2610; wheezing 1680; therapeutic product effect incomplete 1375. FAERS via Open Targets · CHEMBL1441059 · 2026-06-24
Show the evidence
asthma
3143
dyspnoea
2610
wheezing
1680
therapeutic product effect incomplete
1375
cough
1181
obstructive airways disorder
811
4 more recorded rows
blood count abnormal
811
loss of personal independence in daily activities
783
poor quality device used
760
chest discomfort
577
recorded 2026-06-24 · last checked 2026-09-04
Q9
Which 10 reactions does Salbutamol's label not list?
2 label terms; 10 reported and unlisted; 17858afa-dcdf-4612-b475-3b6baadfb639
Show the evidence
asthma
count not stated
blood count abnormal
count not stated
chest discomfort
count not stated
cough
count not stated
dyspnoea
count not stated
loss of personal independence in daily activities
count not stated
4 more recorded rows
obstructive airways disorder
count not stated
poor quality device used
count not stated
therapeutic product effect incomplete
count not stated
wheezing
count not stated
recorded 2026-06-24 · last checked 2026-09-04
Where it is registered
Where it’s registered
Withdrawn in United States, 2023, for "Defective container: empty inhaler and leakage observed through the inhaler valve due to partially missing bottom seat (gasket)." (openFDA drug enforcement Class I recall)
ChEMBL 37 — CC BY-SA 3.0 Unported · ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work · openFDA enforcement — US Government work
✗ required summary fields resolved: 4 required field(s) not terminal: Why people use it, Best-supported result, Biggest unanswered question, Human evidence
✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
✓ source coverage passed: 7 source rows
✓ no critical contamination: no quarantine open
✓ canonical metadata passed: slug and display name present
✓ no raw internal fields: enforced by the copy-contract test over the rendered page
This is a record of evidence. It is not medical advice, and it does not say this substance suits you. Nothing here says any substance on RNAWiki is appropriate for a child.