This page shows what was measured, who it was measured in, and what that does not settle.
What Levosalbutamol does in the body
A tight chest and wheeze — the purified half of the blue inhaler
Levalbuterol does exactly what albuterol does, because it is the working half of albuterol. It lands on the receptor around the airway muscle, raises a second messenger inside the cell, drops the calcium, and the muscle lets go. The pitch was that removing the other half — the mirror-image molecule that does not activate the receptor and hangs around far longer — would make it safer or stronger. Once the trials were done, what the label could say was that it works, and that it works about as well as the mixture it was purified from.
What happened in people
No significant difference between any active arm — including racemic albuterol — in the manufacturer’s crossover pharmacodynamic study
✎ 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.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · a recorded source, not a stored snapshot
That the (S)-enantiomer is clinically harmful, when the manufacturer’s own methacholine study describes it as inert
Where it acts
Beta-2 adrenergic receptors on airway smooth muscle, from the trachea to the terminal bronchioles — the same site, by the same mechanism, as racemic albuterol
Kind of result
The kind of result is not recorded
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 · WDQ1526QJM · read 2026-08-29
Its recorded molecular formula is C13H21NO3•HCl.
US prescribing information · e1a9effb-6ef7-4651-b0ef-a9265600caff · read 2026-08-30
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 124 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.
Comparator
A comparator is whatever the treatment was measured against.
A picture of it, and where the picture fails
It is like the other runner in a race.
Where that stops being true. A race has one winner. A study can show both arms improved.
What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.
The control condition against which the experimental intervention is assessed.
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.
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.
Mean percentage change from baseline FEV1 on day 1 and day 29 in patients 12 and over with mild to moderate asthma
✓ The study showed what it set out to show
Who was studied
Four-week nebulised comparison against racemic albuterol (NDA 020837, section 14)
How many people
362
Study design
Phase 3, randomised, double-blind, placebo-controlled, parallel-group, five arms
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
All active regimens superior to placebo on day 1 and day 29; levalbuterol 0.63 mg and racemic albuterol 2.5 mg clinically comparable at both timepoints; levalbuterol 1.25 mg gave the largest mean change
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 1.25 mg levalbuterol arm delivers about twice the (R)-albuterol exposure of the 2.5 mg racemic arm, per the pharmacokinetic table in the same label. A dose difference is the simpler explanation for the largest mean change, and the trial was not designed to separate the two hypotheses.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Preservative-free unit-dose nebuliser solution at 0.31, 0.63 and 1.25 mg per 3 mL, and a pressurised metered-dose inhaler delivering 45 mcg of levalbuterol base per actuation
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · a recorded source, not a stored snapshot
All active treatments significantly better than placebo; no significant differences between any of the active treatment arms
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. Levalbuterol 1.25 mg produced a slightly higher rate of systemic beta-adrenergic adverse effects than racemic albuterol 2.5 mg. The safety claim for the single isomer runs in the opposite direction to the manufacturer’s own measurement.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Preservative-free unit-dose nebuliser solution at 0.31, 0.63 and 1.25 mg per 3 mL, and a pressurised metered-dose inhaler delivering 45 mcg of levalbuterol base per actuation
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · a recorded source, not a stored snapshot
Time to discharge criteria did not differ; hospitalisation 7.0% against 9.3% (p=0.28); FEV1 after dose 1 0.50 ± 0.43 L against 0.43 ± 0.37 L (p=0.02)
Repeated elsewhere
Failed to Replicate
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 favourable results were subgroup results: patients not on recent steroids (3.8% against 9.3% admission, p=0.03) and the highest quartile of entry plasma (S)-albuterol. The comparison also used non-equivalent (R)-albuterol exposures, which the primary publication does not address.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Preservative-free unit-dose nebuliser solution at 0.31, 0.63 and 1.25 mg per 3 mL, and a pressurised metered-dose inhaler delivering 45 mcg of levalbuterol base per actuation
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · a recorded source, not a stored snapshot
Respiratory rate, oxygen saturation, percentage change in FEV1 and clinical asthma score
✗ The study did not show it
Who was studied
Jat and Khairwa meta-analysis of levalbuterol versus albuterol in acute asthma
How many people
1625
Study design
Systematic review and meta-analysis of 7 randomised trials
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Respiratory rate 0.35 (95% CI -0.81 to 1.51); oxygen saturation -0.29 (-0.68 to 0.10); FEV1 percentage change -28.3 (-59.95 to 3.33); asthma score -1.01 (-5.30 to 3.28); no significant difference in side effects
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. Data were unavailable for two probably eligible trials and some values had to be calculated. The authors concluded levalbuterol should not be used over albuterol in acute asthma.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Preservative-free unit-dose nebuliser solution at 0.31, 0.63 and 1.25 mg per 3 mL, and a pressurised metered-dose inhaler delivering 45 mcg of levalbuterol base per actuation
Interval reported. 95% CI -0
Written into the record, not signed off as a reviewed claim.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · 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.
Start
Levosalbutamol
What a person takes: Preservative-free unit-dose nebuliser solution at 0.31, 0.63 and 1.25 mg per 3 mL, and a pressurised metered-dose inhaler delivering 45 mcg of levalbuterol base per actuation.
The measurement behind this step
The nebuliser vials contain sodium chloride for tonicity, edetate disodium as a stabiliser and sulfuric acid to pH 4.0, and require no dilution. The HFA inhaler is a micronised suspension of levalbuterol tartrate in HFA-134a with dehydrated alcohol and oleic acid, 200 actuations per 15 g canister, primed with four actuations before first use.
Getting in
One molecule instead of two
Albuterol is a fifty-fifty mixture of mirror images. This product contains only the one that works.
╌╌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
Levalbuterol is (R)-albuterol, supplied as the hydrochloride at 275.8 g/mol in the nebuliser solution and as the L-tartrate 2:1 salt at 628.71 g/mol in the HFA inhaler. XOPENEX HFA delivers 45 mcg of levalbuterol free base from the actuator mouthpiece per actuation after priming with four sprays.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · a recorded source, not a stored snapshot
Like albuterol, it never enters the muscle cell. The receptor it binds is on the outer surface.
╌╌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
A saligenin beta-2 agonist acting at the seven-transmembrane beta-2 adrenergic receptor. The 4-hydroxy-3-hydroxymethylphenyl head resists catechol-O-methyltransferase, giving fast onset and short duration; the tert-butylamine buys beta-2 preference over beta-1.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · a recorded source, not a stored snapshot
The same receptor, with the same imperfect selectivity
Beta-2 receptors are mostly in the lung and partly in the heart, which is why this drug also raises the pulse.
──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
The label states that data indicate there are beta receptors in the human heart, 10% to 50% of which are beta-2, that their precise function has not been established, and that all beta-adrenergic agonists can produce significant cardiovascular effects measured by pulse, blood pressure, symptoms or electrocardiographic change — the identical wording used in the racemic albuterol label.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · a recorded source, not a stored snapshot
Identical to albuterol, because it is the working half of albuterol.
╌╌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
Adenylate cyclase activation raises cyclic AMP, protein kinase A inhibits myosin phosphorylation, intracellular ionic calcium falls, smooth muscle relaxes from trachea to terminal bronchiole. Functional antagonism means relaxation occurs irrespective of the spasmogen involved.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · a recorded source, not a stored snapshot
Roughly the same numbers as albuterol, from separate trials that were never designed to rank them.
──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
XOPENEX HFA day 1: median time to a 15% FEV1 increase 5.5 to 10.2 minutes in adults and 4.5 minutes in children; median time to peak 76 to 78 minutes; median duration in responders 3 to 4 hours, up to 6 in some. Nebulised levalbuterol after 4 weeks: mean onset about 10 minutes at 1.25 mg, peak about 1.5 hours, duration about 6 hours.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · a recorded source, not a stored snapshot
And the same limitation as everything else in this class
It opens the airway and does nothing about the inflammation, and needing it more often is a warning 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
Section 5.3: the use of a beta-adrenergic agonist alone may not be adequate to control asthma in many patients, with early consideration to be given to anti-inflammatory agents. Section 5.2: more doses than usual may mark destabilisation. Section 5.5: fatalities have been reported with excessive use of inhaled sympathomimetics.
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · 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 and other reversible airway narrowing aged 4 and over. In practice it was heavily used in United States hospitals during the 2000s, when it cost several times racemic albuterol.
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: “Levalbuterol inhalation solution was studied in 379 pediatric patients less than 6 years of age with asthma or reactive airway disease – (291 patients 2 to 5 years of age, and 88 patients from birth to less than 2 years of age).”
US prescribing information · e1a9effb-6ef7-4651-b0ef-a9265600caff · read 2026-08-30
On older people, the label states: “Clinical studies of levalbuterol inhalation solution did not include sufficient numbers of subjects aged 65 years and older to determine whether they respond differently from younger subjects.”
US prescribing information · e1a9effb-6ef7-4651-b0ef-a9265600caff · read 2026-08-30
On people who are pregnant, the label states: “Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to asthma medication, including levalbuterol inhalation solution during pregnancy.”
US prescribing information · e1a9effb-6ef7-4651-b0ef-a9265600caff · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary There are no available data on the presence of levalbuterol in human milk, the effects on the breastfed child, or the effects on milk production.”
US prescribing information · e1a9effb-6ef7-4651-b0ef-a9265600caff · read 2026-08-30
On people with reduced kidney function, the label states: “Albuterol is known to be substantially excreted by the kidney, and the risk of toxic reactions may be greater in patients with impaired renal function.”
US prescribing information · e1a9effb-6ef7-4651-b0ef-a9265600caff · read 2026-08-30
Where the result stopped carrying
The primary endpoint of the largest acute asthma trial: time to meet discharge criteria did not differ
The pooled meta-analysis found no difference on any measured outcome and recommended against preferring levalbuterol
The safety rationale reversed: the marketed levalbuterol dose caused slightly more systemic effects than the marketed racemic dose
FDA classified the original application Type 3, a new dosage form, rather than a new molecular entity
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.
The change is too small to feel
A real change can still sit below what a person notices.
On this record: Now within about seven per cent of racemic albuterol at pharmacy acquisition cost, with no change in the evidence that once justified the gap
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.
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.
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
Preservative-free unit-dose nebuliser solution at 0.31, 0.63 and 1.25 mg per 3 mL, and a pressurised metered-dose inhaler delivering 45 mcg of levalbuterol base per actuation
✎ 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
0, and require no dilution.
✎ 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 HFA inhaler is a micronised suspension of levalbuterol tartrate in HFA-134a with dehydrated alcohol and oleic acid, 200 actuations per 15 g canister, primed with four actuations before first use.
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
Identical in kind to racemic albuterol and worded identically in the label. Paradoxical bronchospasm, which may be life threatening and most often follows the first use of a new canister. Fatalities reported with excessive use of inhaled sympathomimetics. Cardiovascular effects including pulse and blood pressure change and electrocardiogram changes of unknown significance. Immediate hypersensitivity reactions. Hypokalaemia and changes in blood glucose. Needing more doses than usual is a marker of destabilisation, and the drug is not a substitute for corticosteroids.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Where this came from
Levalbuterol hydrochloride inhalation solution United States prescribing information — Description 11, Mechanism of Action 12.1, Pharmacodynamics 12.2 includ… · a recorded source, not a stored snapshot
XOPENEX HFA (levalbuterol tartrate) inhalation aerosol United States prescribing information — Indications 1.1, Warnings 5.1 to 5.8, Description 11, Mechanis… · 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
Preservative-free unit-dose nebuliser solution at 0.31, 0.63 and 1.25 mg per 3 mL, and a pressurised metered-dose inhaler delivering 45 mcg of levalbuterol base per actuation
✎ 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
0, and require no dilution.
✎ 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 HFA inhaler is a micronised suspension of levalbuterol tartrate in HFA-134a with dehydrated alcohol and oleic acid, 200 actuations per 15 g canister, primed with four actuations before first use.
No source is stored against this line.
What is recorded as being sold
46 products list this as an active ingredient in the United States drug directory. 46 of them contain it and nothing else.
FDA National Drug Code directory · 48954-719 · read 2026-08-29
They are sold as aerosol, metered, powder, solution and solution, concentrate, taken oral and respiratory (inhalation).
FDA National Drug Code directory · 48954-719 · 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 · 48954-719 · read 2026-08-29
20 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 · ac85703a-17a2-4f0b-87f4-78f1756d2f85 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · ac85703a-17a2-4f0b-87f4-78f1756d2f85 · read 2026-08-29
LEVALBUTEROL is respiratory (inhalation) at 3 DOSAGE FORMS AND STRENGTHS Inhalation Solution Concentrate: 0.5 mL unit-dose vials containing 1.25 mg of levalbuterol that must be diluted before use., recorded as fda label in effect 2023-10-31 in the United States.
US prescribing information · e1a9effb-6ef7-4651-b0ef-a9265600caff · read 2026-08-30
Recorded price in US: 0.2411–0.4072 USD per one millilitre, across 27 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 Levosalbutamol 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 the (S)-enantiomer is clinically harmful, when the manufacturer’s own methacholine study describes it as inert
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 levalbuterol is safer than racemic albuterol, when the label reports slightly more systemic beta-adrenergic effects at the marketed doses
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 small first-dose FEV1 advantage in the acute trial reflects the isomer rather than the roughly twofold higher (R)-albuterol exposure at the doses compared
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 a subgroup of patients not on recent steroids, identified after a missed primary endpoint, defines a population in whom the drug is preferable
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 Levosalbutamol 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.
The label reports no significant difference from the drug it replaced
In plain words
The whole point of levalbuterol is that it should beat ordinary albuterol. The crossover study printed in its own prescribing information compared three doses of levalbuterol with racemic albuterol and found no significant difference between any of them.
What was measured
That the purified (R)-enantiomer is clinically superior to racemic albuterol — a claim the manufacturer’s own comparative data in the label do not support
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Section 12.2 of the levalbuterol inhalation solution label describes a randomised, double-blind, placebo-controlled crossover study in 20 adults with mild to moderate asthma given single doses of levalbuterol 0.31, 0.63 and 1.25 mg and racemic albuterol 2.5 mg. All active treatments produced significantly greater bronchodilation than placebo, and — in the label’s own words — there were no significant differences between any of the active treatment arms. The bronchodilator responses to levalbuterol 1.25 mg and racemic albuterol 2.5 mg were clinically comparable over the 6-hour evaluation, except for a slightly longer duration after levalbuterol. The 4-week parallel-group study in 362 patients reported that levalbuterol 0.63 mg and racemic albuterol 2.5 mg produced clinically comparable mean percentage change from baseline FEV1 on day 1 and day 29. A cumulative-dose study found comparable efficacy and comparable safety after 5 mg of levalbuterol and 10 mg of racemic albuterol. In children aged 6 to 11, onset and duration of levalbuterol were clinically comparable to racemic albuterol. The XOPENEX HFA registration trials in 748 adults included a marketed albuterol HFA inhaler as an active control and the label reports superiority to placebo only; no superiority to the racemate is claimed anywhere in the document.
Source
Levalbuterol inhalation solution United States prescribing information, sections 12.2 and 14; XOPENEX HFA prescribing information, section 14.1 (NDA 020837, NDA 021730)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
contested
Review state
Written into the record, not signed off as a reviewed claim
It produced slightly more systemic side effects, not fewer
In plain words
The safety argument was that removing the inactive half would reduce tremor and heart-racing. In the manufacturer’s own study, the marketed levalbuterol dose caused slightly more of those effects than the marketed albuterol dose, not fewer.
What was measured
Rate of systemic beta-adrenergic adverse effects, and (R)-albuterol AUC, at the marketed doses of each product
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Section 12.2 states that systemic beta-adrenergic adverse effects were observed with all active doses and were generally dose-related for (R)-albuterol, and that levalbuterol 1.25 mg produced a slightly higher rate of systemic beta-adrenergic adverse effects than racemic albuterol 2.5 mg. Section 12.3 explains why: a single 1.25 mg dose of levalbuterol produced an (R)-albuterol area under the curve of 3.3 ng·hr/mL against 1.7 ng·hr/mL for a single 2.5 mg dose of racemic albuterol — approximately twice the exposure to the active molecule. The two marketed doses are not equivalent in (R)-albuterol delivered, which means the small efficacy edge and the small side-effect edge point in the directions a higher dose of the same drug would produce. Nothing in that pattern requires the (S)-enantiomer hypothesis to explain it.
Source
Levalbuterol inhalation solution United States prescribing information, sections 12.2 and 12.3, Table 6 (NDA 020837)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
contested
Review state
Written into the record, not signed off as a reviewed claim
The manufacturer tested whether the discarded isomer is harmful, and it is not
In plain words
(S)-albuterol was given on its own to twelve people and challenged with a bronchoconstrictor. It offered almost no protection at twenty minutes and none at three hours. It did not make anything worse either.
What was measured
Bronchoprotection against methacholine challenge at 20 and 180 minutes, (S)-albuterol against placebo, racemate and levalbuterol
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Section 12.2 describes a randomised, double-blind, placebo-controlled crossover study in which 12 adults with mild to moderate asthma were challenged with inhaled methacholine chloride at 20 and 180 minutes after a single nebulised dose of racemic albuterol 2.5 mg, levalbuterol 1.25 mg, (S)-albuterol 1.25 mg or placebo. All three actives had a protective effect at 20 minutes, although the effect of (S)-albuterol was minimal. At 180 minutes, levalbuterol’s protection was comparable to racemic albuterol’s, and (S)-albuterol had no bronchoprotective effect. That is a description of an inert molecule, not an actively harmful one, and it is the strongest human test of the (S)-albuterol hypothesis carried in the product’s own labelling. The pharmacological argument for harm — that (S)-albuterol raises intracellular calcium and enhances airway reactivity, and that it is cleared far more slowly so accumulates with repeated dosing — remains a laboratory and pharmacokinetic argument that this study did not confirm clinically.
Source
Levalbuterol inhalation solution United States prescribing information, section 12.2 (NDA 020837)
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
Seven trials, 1,625 patients, no difference on anything
In plain words
When all the acute asthma trials were pooled, breathing rate, oxygen level, lung function and asthma score were all the same on levalbuterol as on albuterol, and so were the side effects.
What was measured
Respiratory rate, oxygen saturation, percentage change in FEV1 and clinical asthma score, levalbuterol against albuterol in acute asthma
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The systematic review and meta-analysis of levalbuterol against albuterol in acute asthma across all ages identified seven eligible randomised trials with 1,625 participants. Mean differences with 95% confidence intervals were 0.35 (-0.81 to 1.51) for respiratory rate, -0.29 (-0.68 to 0.10) for oxygen saturation, -28.3 (-59.95 to 3.33) for percentage change in FEV1, and -1.01 (-5.30 to 3.28) for clinical asthma score. None was significant. There were no significant differences in side effects. The authors concluded that levalbuterol was not superior to albuterol on efficacy or safety and that levalbuterol should not be used over albuterol for acute asthma. Two probably eligible trials could not contribute data and some values had to be calculated, which the authors listed as limitations — but the confidence intervals are wide around zero rather than narrow around a benefit.
Written into the record, not signed off as a reviewed claim
The largest acute trial missed its primary endpoint and was reported on subgroups
In plain words
Six hundred and twenty-seven adults in emergency departments were randomised. Time to being ready for discharge — the question the trial was built to answer — did not differ. What got reported was a lung-function difference and an admission benefit in one part of the population.
What was measured
Time to meet discharge criteria, and hospitalisation rate, in 627 adults
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The XOPENEX Acute Severe Asthma Study randomised adults with FEV1 20% to 55% of predicted to nebulised levalbuterol 1.25 mg (n=315) or racemic albuterol 2.5 mg (n=312), all with prednisone, dosed every 20 minutes for the first hour then every 40 minutes for three further doses and as necessary to 24 hours. The primary endpoint, time to meet discharge criteria, did not differ between treatments. FEV1 improvement after dose 1 was greater with levalbuterol in the intention-to-treat group, 0.50 ± 0.43 L against 0.43 ± 0.37 L (p=0.02). Hospitalisation was 7.0% against 9.3% overall and did not differ (p=0.28). The reported advantages were in subgroups: patients not on recent steroid therapy (admission 3.8% against 9.3%, p=0.03) and patients in the highest quartile of entry plasma (S)-albuterol concentration. Relapse at 30 days was 5% in both arms. Note also the dose asymmetry from the label — 1.25 mg of levalbuterol delivers about twice the (R)-albuterol exposure of 2.5 mg of racemic albuterol — which is an alternative explanation for a small first-dose FEV1 difference that requires no isomer hypothesis at all.
Written into the record, not signed off as a reviewed claim
The price argument ended without the evidence changing
In plain words
It once cost up to five times racemic albuterol and that gap was the substance of every argument about it. Today the two are within seven per cent of each other at what pharmacies pay, and nothing was ever demonstrated in between.
What was measured
Acquisition cost per millilitre of levalbuterol against racemic albuterol, at launch and in 2026
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
A 2000 analysis in Pharmacotherapy titled "Levalbuterol nebulizer solution: is it worth five times the cost of albuterol?" concluded that published studies indicated levalbuterol was neither safer nor more effective than an equimolar dose of racemic albuterol, that those studies had been conducted in stable asthma at the top of the dose-response curve rather than in the acute exacerbations where nebulised bronchodilators are actually used, that the manufacturer’s recommended dose was therefore likely too low for rescue therapy, and that levalbuterol may cost as much as five times more depending on purchase method. At CMS National Average Drug Acquisition Cost in August 2026, levalbuterol solution is US$0.2676 per millilitre and racemic albuterol solution is US$0.2505 — a 6.8% difference. The registration classification is worth noting alongside it: NDA 020837 was approved on 25 March 1999 as Type 3, a new dosage form, not as a new molecular entity, because the active enantiomer was already being administered inside the racemate.
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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.
The purified (R)-enantiomer of albuterol, marketed on the harm of the discarded (S)-isomer, whose own label reports no significant difference from racemic albuterol on lung function, a slightly higher rate of systemic beta-adrenergic adverse effects, and roughly twice the (R)-albuterol exposure per marketed dose — and whose seven-trial, 1,625-patient meta-analysis in acute asthma found no difference in respiratory rate, oxygen saturation, FEV1 or asthma score.
Recorded evidence blocks (8)
Q1
On the Levosalbutamol label: indicated for what?
"Levalbuterol Inhalation Solution, USP is indicated for the treatment or prevention of bronchospasm in adults, adolescents, and children 6 years of age and older with reversible obstructive airway disease. Levalbuterol Inhalation Solution, USP is a beta 2 -adrenergic agonist indicated for: Treatment or prevention of…": indications and usage on Levosalbutamol's label. DailyMed label · 56cb1f4b-ddf4-0661-e063-6394a90a9c45 · 2026-07-17
Q2
24 registered trials of Levosalbutamol — at which phases?
"Unable to enroll r/t study design \& staffing issues. The trial terminated."; 2 of 24 registered studies
Show the evidence
Trial
NCT00819637
terminated; "Unable to enroll r/t study design \& staffing issues. The trial terminated."
NCT00830882
withdrawn; "Lack of funding"
recorded 2026-09-01 · last checked 2026-09-04
Q4
Human studies of Levosalbutamol used Levalbuterol 1.25 mg — over how long?
Human studies of Levosalbutamol used "Levalbuterol 1.25 mg". ClinicalTrials.gov · 2026-09-01
2 recorded entries; human; also "levalbuterol 180 mcg"
Show the evidence
human
NCT00667407
Levalbuterol 1.25 mg
NCT01656811
levalbuterol 180 mcg
recorded 2026-09-01 · last checked 2026-09-04
Q5
Which 12 trials of Levosalbutamol posted no result?
Posted no result
12 of 12 completed trials
Registrations
NCT00685126, NCT01656811, NCT00667407, NCT00665600, NCT00685425 and NCT00073840, and 6 more
Completion dates
oldest 2002-07; newest 2012-04
Show the evidence
Trial
NCT00685126
2002-07
NCT01656811
2002-07
NCT00667407
2002-08
NCT00665600
2003-03
NCT00685425
2003-03
NCT00073840
2003-06
6 further recorded trials
NCT00685347
2003-06
NCT00667797
2005-05
NCT00064389
2005-07
NCT00268723
2006-02
NCT00583986
2006-03
NCT00831376
2012-04
Q6
At the median, Levosalbutamol's trials enrolled 85 people — anything larger?
Median enrolment
85
Largest enrolment
746
Registered trials counted
24
Q7
What do 3904 spontaneous reports say about Levosalbutamol — 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.
Levosalbutamol appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 3904 reaction mentions were counted: asthma 925; dyspnoea 734; wheezing 435; cough 412. FAERS via Open Targets · CHEMBL1002 · 2026-06-24
Show the evidence
asthma
925
dyspnoea
734
wheezing
435
cough
412
blood count abnormal
262
pneumonia
254
4 more recorded rows
therapeutic product effect incomplete
252
obstructive airways disorder
226
chest discomfort
211
productive cough
193
recorded 2026-06-24 · last checked 2026-09-04
Q8
Which 10 reactions does Levosalbutamol's label not list?
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
✗ 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: 6 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.