This page shows what was measured, who it was measured in, and what that does not settle.
What Montelukast does in the body
Montelukast sits on the receptor those messengers use and stops them landing.
When an allergic reaction fires, cells release leukotrienes: chemical messengers that make the airway lining swell, the muscle around it squeeze, and the nose block. Because it blocks only one family of messenger out of many, it takes away part of the inflammation rather than most of it, which is why a steroid inhaler that suppresses the whole process works better. It is a tablet, so it reaches everywhere the blood goes, including the brain.
Why people take it. Asthma taken as a daily tablet, and hay fever when other drugs fail
What happened in people
A daytime nasal symptom difference from placebo of -0.13 in seasonal and -0.08 in perennial allergic rhinitis, on a 0-3 scale
✎ 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.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
Boxed warning and patient Medication Guide required 4 March 2020, with the allergic rhinitis indication narrowed to patients failed by or intolerant of alternatives
Where it acts
CysLT1 receptors in the airway and nasal mucosa. The label also records that montelukast distributes into the brain in rats, which is the only mechanistic fact it offers about the boxed warning.
Kind of result
Symptoms and quality of life
Supervision
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
What the registries record it as
Its recorded molecular formula is C35H35ClNNaO3S, weighing 608.18.
US prescribing information · c69ab399-8ea6-4002-9271-b6a57c862b14 · read 2026-08-30
Where each sentence above came from
A person wrote this explanation into the record, with the studies named in the path below.
The recorded use, written for a reader without medical training. Not signed off.
A limit recorded against this substance. Not signed off as a reviewed claim.
The four opening statements run to 123 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.
Co-primary morning FEV1 and daytime asthma symptoms over 12 weeks in patients aged 15 and over with mild to moderate asthma
✓ The study showed what it set out to show
Who was studied
Two 12-week placebo-controlled asthma registration trials (NDA 020829)
How many people
1576
Study design
Phase 3, randomised, double-blind, placebo- and active-controlled
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
FEV1 +13.0% against +4.2% on placebo, absolute 0.32 L against 0.10 L, between-group difference 0.22 L (95% CI 0.17 to 0.27), p<0.001; daytime symptom score -0.49 against -0.26 on a 0-6 scale, p<0.001
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 publication reported adverse events and discontinuations as comparable to placebo. Twelve weeks in 795 treated patients is not a design that could detect a rare psychiatric outcome, and the boxed warning that arrived 22 years later came from postmarketing reports, not from this programme.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral, once daily: 10 mg film-coated tablet, 4 mg and 5 mg chewable tablets, and 4 mg oral granules for infants from 6 months
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
Phase 4, randomised, double-blind, 48 weeks, three parallel regimens
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Fluticasone 64.2% against montelukast 52.5% asthma control days, p=0.004; fluticasone superior on every other control outcome; 48-week growth 5.3 cm on fluticasone against 5.7 cm on montelukast, not significantly different
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 growth result is the one that matters for the argument usually made in montelukast’s favour. Over 48 weeks the steroid inhaler did not measurably cost these children height, and it did measurably control their asthma better.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral, once daily: 10 mg film-coated tablet, 4 mg and 5 mg chewable tablets, and 4 mg oral granules for infants from 6 months
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
Number of patients with at least one exacerbation requiring systemic corticosteroids
✗ The study did not show it
Who was studied
Cochrane anti-leukotrienes versus inhaled corticosteroids as monotherapy (CD002314.pub3)
How many people
13338
Study design
Systematic review and meta-analysis of 56 randomised trials
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
RR 1.51 (95% CI 1.17 to 1.96) against the anti-leukotriene in 6,077 participants; hospital admission RR 3.33 (95% CI 1.02 to 10.94); FEV1 110 mL lower; withdrawal for poor control RR 2.56 (95% CI 2.01 to 3.27)
Repeated elsewhere
Replicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. The disadvantage widened with disease severity: RR 2.03 (95% CI 1.41 to 2.91) in moderate airway obstruction against RR 1.25 (95% CI 0.97 to 1.61) in mild. The sicker the patient, the worse the substitution.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral, once daily: 10 mg film-coated tablet, 4 mg and 5 mg chewable tablets, and 4 mg oral granules for infants from 6 months
Interval reported. 95% CI 1
Written into the record, not signed off as a reviewed claim.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
Mean 2.0 (SD 2.6) against 2.3 (2.7); incidence rate ratio 0.88 (95% CI 0.77 to 1.01), p=0.06
Repeated elsewhere
Unreplicated
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 prespecified ALOX5 5/5 genotype stratum separated (IRR 0.80, 95% CI 0.68 to 0.95) and the other stratum did not, but the interaction test itself was p=0.08. A subgroup that only appears when the overall result is negative needs its own trial, and did not get one.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral, once daily: 10 mg film-coated tablet, 4 mg and 5 mg chewable tablets, and 4 mg oral granules for infants from 6 months
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
Mean change from baseline in daytime nasal symptoms score on a 0-3 categorical scale
✓ The study showed what it set out to show
Who was studied
Seasonal allergic rhinitis trial with loratadine active control (NDA 020829, section 14.3)
How many people
1294
Study design
Phase 3, randomised, double-blind, placebo- and active-controlled
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Montelukast -0.39 against placebo -0.26, difference -0.13 (95% CI -0.21 to -0.06), p≤0.001; loratadine -0.46, difference from placebo -0.24 (95% CI -0.31 to -0.17)
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. The label states the study was not designed for statistical comparison between montelukast and the active control. It nonetheless prints both differences from placebo in the same table, and the antihistamine’s is nearly twice the size.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral, once daily: 10 mg film-coated tablet, 4 mg and 5 mg chewable tablets, and 4 mg oral granules for infants from 6 months
Interval reported. 95% CI -0
Written into the record, not signed off as a reviewed claim.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
RNAWiki holds 5 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: Binds the cysteinyl leukotriene CysLT1 receptor found in the human airway, including airway smooth muscle cells and airway macrophages
US prescribing information · 04b3faff-1ea1-4d2a-aa31-9d6e742e1759 · read 2026-08-27
Nose and upper airway: In allergic rhinitis, cysteinyl leukotrienes are released from the nasal mucosa after allergen exposure and are associated with symptoms
US prescribing information · 04b3faff-1ea1-4d2a-aa31-9d6e742e1759 · read 2026-08-27
Start
Montelukast
What a person takes: Oral, once daily: 10 mg film-coated tablet, 4 mg and 5 mg chewable tablets, and 4 mg oral granules for infants from 6 months.
The measurement behind this step
The chewable tablets contain aspartame, and the label directs that patients with phenylketonuria be told the 4 mg and 5 mg chewables contain phenylalanine. Dosing is in the evening for asthma; for seasonal allergic rhinitis the label records efficacy with morning or evening administration.
Getting in
A tablet, so it goes everywhere
Unlike an inhaler, this is swallowed once a day and carried by the blood to every tissue — including, the label notes, the brain.
──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
Orally active leukotriene receptor antagonist, taken as the sodium salt at 10 mg in adults, 5 mg or 4 mg chewable in children and 4 mg oral granules in infants. Section 5.1 of the label records that animal studies showed montelukast distributes into the brain in rats, cross-referenced from the neuropsychiatric warning to the pharmacokinetics section.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
Mast cells and eosinophils release cysteinyl leukotrienes during an allergic reaction. These are the molecules montelukast is designed to intercept.
╌╌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
LTC4, LTD4 and LTE4 are arachidonic acid products released from mast cells and eosinophils. In asthma their effects include airway oedema, smooth muscle contraction and altered cellular activity in the inflammatory process; in allergic rhinitis they are released from nasal mucosa after allergen exposure in both early- and late-phase reactions.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
It occupies one receptor and leaves the others alone
Montelukast sits in the CysLT1 receptor without switching it on, so the leukotrienes arrive and find the seat taken.
╌╌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
High-affinity, selective binding to CysLT1 in preference to prostanoid, cholinergic and beta-adrenergic receptors, inhibiting the physiologic actions of LTD4 without agonist activity. CysLT1 is present on airway smooth muscle cells, airway macrophages, eosinophils and certain myeloid stem cells.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
One inflammatory pathway closes; the rest stay open
Blocking leukotrienes removes part of the swelling and squeezing. Histamine, cytokines and everything else the airway lining produces carry on.
╌╌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
This is the pharmacological reason a receptor antagonist for one mediator family underperforms a glucocorticoid, which suppresses transcription across the whole inflammatory programme. It shows up as a 110 mL FEV1 deficit and a 1.51 relative risk of steroid-requiring exacerbation in the Cochrane monotherapy comparison.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
Lung function rises within a day and holds for twelve weeks
The measured benefit in asthma arrives almost immediately and does not fade, and stopping it produced no rebound.
╌╌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
FEV1 +13.0% against +4.2% on placebo over 12 weeks, a 0.22 L between-group difference (95% CI 0.17 to 0.27, p<0.001); near-maximal effect on symptoms and reliever use within the first day; asthma attacks 15.6% against 27.3% in the multinational trial. A randomised subset switched to placebo for three weeks showed neither tolerance nor rebound worsening.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · a recorded source, not a stored snapshot
And something happens in the brain that nobody has explained
Agitation, nightmares, low mood and, rarely, suicidal thinking. The warning is the strongest the FDA issues, and the label says the mechanism is not understood.
──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
Boxed warning since 4 March 2020. Reported events include agitation, aggression, anxiousness, depression, disorientation, dream abnormalities, hallucinations, insomnia, irritability, memory impairment, obsessive-compulsive symptoms, somnambulism, stuttering, tic, tremor and suicidal thoughts and behaviour including suicide, in patients with and without prior psychiatric history, and some reported after discontinuation. Matched-cohort data put the paediatric one-year number needed to harm at 58 for any neuropsychiatric outcome.
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · 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 persistent asthma, people who wheeze on exercise, and people with allergic rhinitis — the last group only, since March 2020, when other allergy treatments have not worked or cannot be tolerated.
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: “Safety and effectiveness of montelukast sodium for asthma have been established in pediatric patients with asthma 6 to 14 years of age.”
US prescribing information · c69ab399-8ea6-4002-9271-b6a57c862b14 · read 2026-08-30
On older people, the label states: “Of the total number of subjects in clinical studies of montelukast, 3.5% were 65 years of age and over, and 0.4% were 75 years of age and over.”
US prescribing information · c69ab399-8ea6-4002-9271-b6a57c862b14 · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary Available data from published prospective and retrospective cohort studies over decades with montelukast use in pregnant women have not established a drug-associated risk of major birth defects [see Data] .”
US prescribing information · c69ab399-8ea6-4002-9271-b6a57c862b14 · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary A published clinical lactation study reports the presence of montelukast in human milk.”
US prescribing information · c69ab399-8ea6-4002-9271-b6a57c862b14 · read 2026-08-30
On people with reduced liver function, the label states: “No dosage adjustment is recommended required in patients with mild-to-moderate hepatic insufficiency [see Clinical Pharmacology ( 12.3 )].”
US prescribing information · c69ab399-8ea6-4002-9271-b6a57c862b14 · read 2026-08-30
On people with reduced kidney function, the label states: “No dosage adjustment is recommended in patients with renal insufficiency [see Clinical Pharmacology ( 12.3 )].”
US prescribing information · c69ab399-8ea6-4002-9271-b6a57c862b14 · read 2026-08-30
Where the result stopped carrying
One of five seasonal and one of two perennial allergic rhinitis registration trials did not demonstrate efficacy
In the perennial trial with a cetirizine comparator, montelukast’s difference from placebo was -0.04 (95% CI -0.09 to 0.01) and cetirizine’s was -0.10 (95% CI -0.19 to -0.01)
Intermittent use in 1,358 wheezy preschool children did not reduce unscheduled medical attendances (IRR 0.88, p=0.06)
The neuropsychiatric signal sat in the warnings section for most of two decades before it was judged to outweigh the benefit in mild disease
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 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 (11)
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.
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
Oral, once daily: 10 mg film-coated tablet, 4 mg and 5 mg chewable tablets, and 4 mg oral granules for infants from 6 months
✎ 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
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Suppression classes recorded: S6.
No source is stored against this line.
What is in the pack
The chewable tablets contain aspartame, and the label directs that patients with phenylketonuria be told the 4 mg and 5 mg chewables contain phenylalanine. Dosing is in the evening for asthma; for seasonal allergic rhinitis the label records efficacy with morning or evening administration.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold and what that means for what is in the pack.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
Boxed warning for serious neuropsychiatric events including suicidal thoughts and behaviour, in patients with and without prior psychiatric history, sometimes persisting after discontinuation. Not for acute bronchospasm or status asthmaticus, and rescue medication must remain available. Must not be abruptly substituted for inhaled or oral corticosteroids. Systemic eosinophilia, sometimes presenting with clinical features of vasculitis consistent with Churg-Strauss syndrome, has been reported, sometimes in association with reduction of oral corticosteroid therapy. Aspirin-sensitive patients must continue to avoid aspirin and non-steroidal anti-inflammatory drugs while taking it.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Where this came from
SINGULAIR (montelukast sodium) United States prescribing information — Boxed Warning, Indications 1.1 to 1.4, Warnings 5.1 to 5.6, Description 11, Clinical P… · a recorded source, not a stored snapshot
FDA Drug Safety Communication, 4 March 2020 — FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Si… · 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
Oral, once daily: 10 mg film-coated tablet, 4 mg and 5 mg chewable tablets, and 4 mg oral granules for infants from 6 months
✎ 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
Dosing is in the evening for asthma; for seasonal allergic rhinitis the label records efficacy with morning or evening administration.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on which forms are sold and how they compare.
No source is stored against this line.
What is recorded as being sold
116 products list this as an active ingredient in the United States drug directory. 116 of them contain it and nothing else.
FDA National Drug Code directory · 82009-009 · read 2026-08-29
They are sold as granule, powder, tablet, tablet, chewable, tablet, coated and tablet, film coated, taken oral.
FDA National Drug Code directory · 82009-009 · read 2026-08-29
The regulator's established pharmacologic class for it is leukotriene receptor antagonist [epc] and leukotriene receptor antagonists [moa].
FDA National Drug Code directory · 82009-009 · read 2026-08-29
68 published labels name it as an active ingredient. 68 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · c69ab399-8ea6-4002-9271-b6a57c862b14 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · c69ab399-8ea6-4002-9271-b6a57c862b14 · read 2026-08-29
montelukast sodium is chewable tablets at Chewable tablets: 4 mg and 5 mg, recorded as prescription product; fda label in effect 2026-03-05 in the United States.
US prescribing information · 04b3faff-1ea1-4d2a-aa31-9d6e742e1759 · read 2026-08-27
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.
Self-experiment planning is not offered for a prescription or clinician-supervised medicine. The questions below are for a clinician or pharmacist.
Questions worth asking
Which of the trials of Montelukast 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 a tablet acting on one mediator family can replace an inhaled corticosteroid, which the randomised comparison contradicts on every endpoint
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the allergic rhinitis benefit is comparable to an antihistamine’s, when the label’s own tables show loratadine and cetirizine doing better against the same placebos
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 neuropsychiatric events have an established mechanism — the label states they are not well understood and the only supporting observation is brain distribution in rats
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 ALOX5 genotype subgroup in WAIT identifies a responsive population, on an interaction test that did not itself reach significance
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 Montelukast 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 asthma effect is real and it was measured properly
In plain words
In the trial that got it approved, lung function improved by 13% against 4% on placebo, and the effect was there within the first day and had not worn off at twelve weeks.
What was measured
Mean percentage change from baseline in morning FEV1 over 12 weeks, and asthma attack rate as a secondary endpoint
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Two similarly designed randomised, 12-week, double-blind, placebo-controlled trials enrolled 1,576 patients aged 15 and over with mild or moderate asthma — 795 on montelukast, 530 on placebo, 251 on an active control — with mean baseline FEV1 at 66% of predicted. In the United States trial the co-primary endpoint of morning FEV1 improved by 13.0% from baseline against 4.2% on placebo (p<0.001), an absolute 0.32 L against 0.10 L, a between-group difference of 0.22 L (95% CI 0.17 to 0.27). The multinational trial gave the same result and added a secondary outcome that matters more: asthma attacks requiring unscheduled care or systemic corticosteroids occurred in 15.6% against 27.3% on placebo (p<0.001). Daytime symptom score fell 0.49 against 0.26 on a 0-6 scale, beta-agonist use 1.65 against 0.42 puffs per day. A randomised subset was switched to placebo for three weeks at the end and showed no rebound.
Written into the record, not signed off as a reviewed claim
The boxed warning took twenty-two years
In plain words
Montelukast was approved in 1998. The strongest warning the FDA can require — for agitation, depression and suicide — was added in March 2020, and at the same time the hay fever indication was cut back to people other drugs had failed.
What was measured
Regulatory benefit-risk determination — warning class and indication scope, 1998 against 2020
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
FDA issued its Drug Safety Communication on 4 March 2020, stating that montelukast prescribing information already included warnings about mental health side effects including suicidal thoughts or actions, but that many health care professionals and patients were not aware of the risk. After an extensive review and a panel of outside experts, FDA required a boxed warning and a new patient Medication Guide, and determined that for allergic rhinitis montelukast should be reserved for those not treated effectively by, or unable to tolerate, other allergy medicines. The boxed warning now reads that because of the risk of neuropsychiatric events, the benefits may not outweigh the risks in some patients, particularly when the symptoms of disease may be mild and adequately treated with alternative therapies. The reasoning is a benefit-risk reversal rather than new evidence of harm: the harm signal was in the label already, and what changed was the judgement that a small benefit could not carry it.
Source
FDA Drug Safety Communication, 4 March 2020: FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Singulair); advises restricting use for allergic rhinitis
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
In its own hay fever trials the antihistamine did better
In plain words
Two of the registration trials for allergic rhinitis included an ordinary antihistamine as a comparator. In one, loratadine beat placebo by nearly twice as much as montelukast did. In the other, cetirizine separated from placebo and montelukast did not.
What was measured
Mean change from baseline in daytime nasal symptom score on a 0-3 scale against placebo, montelukast versus loratadine and cetirizine
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Seasonal allergic rhinitis was studied in five trials enrolling 5,029 patients; four of the five showed a significant reduction in daytime nasal symptom score. In the trial reported on the label, on a 0-3 scale, montelukast changed the score by -0.39 against placebo’s -0.26, a difference of -0.13 (95% CI -0.21 to -0.06, p≤0.001) in 344 patients, while loratadine changed it by -0.46, a difference of -0.24 (95% CI -0.31 to -0.17) in 599 patients. Perennial allergic rhinitis was studied in two trials enrolling 3,357 patients, of which the label says only one demonstrated efficacy: there montelukast’s difference from placebo was -0.08 (95% CI -0.12 to -0.04) in 1,000 patients. In the other, montelukast’s estimated difference from placebo was -0.04 (95% CI -0.09 to 0.01), which includes zero, while the cetirizine comparator’s was -0.10 (95% CI -0.19 to -0.01), which does not. The label states in both cases that the study was not designed for statistical comparison between montelukast and the active control, and that caveat is doing a great deal of work: it means the manufacturer never formally tested the comparison whose numbers its own label prints.
Source
SINGULAIR United States prescribing information, section 14.3, Tables 9 and 10 and the accompanying perennial rhinitis text (NDA 020829)
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
As a lone asthma controller it loses to an inhaled steroid on every endpoint
In plain words
Fifty-six randomised trials in more than thirteen thousand people compared a leukotriene tablet with a steroid inhaler used alone. The tablet group had half again as many attacks needing steroid tablets, and more than three times as many needing hospital.
What was measured
Exacerbations requiring systemic corticosteroids or hospital admission, anti-leukotriene monotherapy against inhaled corticosteroid monotherapy
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The Cochrane review of anti-leukotrienes against inhaled corticosteroids as monotherapy included 56 trials contributing data on 10,005 adults and 3,333 children with mild or moderate persistent asthma, at a median comparator dose of 200 mcg/day of HFA beclometasone or equivalent. Patients on anti-leukotrienes were more likely to have an exacerbation requiring systemic corticosteroids: RR 1.51 (95% CI 1.17 to 1.96), one additional such exacerbation for every 28 patients treated with the tablet instead of the inhaler. Exacerbations requiring hospital admission: RR 3.33 (95% CI 1.02 to 10.94). FEV1 was 110 mL lower. Withdrawal due to poor asthma control: RR 2.56 (95% CI 2.01 to 3.27), one extra withdrawal for every 31 patients. The disadvantage was significantly larger in moderate than in mild airway obstruction (RR 2.03 against RR 1.25). Side-effect risk did not differ. In children specifically, the 285-patient PACT trial found fluticasone superior to montelukast on asthma control days, 64.2% against 52.5% (p=0.004), and on every other control outcome, with no difference in 48-week growth.
Written into the record, not signed off as a reviewed claim
In preschool wheeze it did not work
In plain words
The largest trial ever run in wheezy toddlers gave montelukast at the start of each episode to 669 children and placebo to 677. The number of unscheduled medical visits was not significantly different.
What was measured
Number of unscheduled medical attendances for wheezing episodes over 12 months
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The WAIT trial randomised 1,358 children aged 10 months to 5 years with two or more wheeze episodes to intermittent montelukast or placebo given by parents at each episode over 12 months, stratified by ALOX5 promoter Sp1-binding motif copy number because that genotype had been reported to modify response in adults. Primary outcome data were available for 1,308 (96%). Unscheduled medical attendances for wheezing episodes were a mean 2.0 (SD 2.6) on montelukast against 2.3 (2.7) on placebo, incidence rate ratio 0.88 (95% CI 0.77 to 1.01, p=0.06) — not significant. The 5/5 genotype stratum did separate (IRR 0.80, 95% CI 0.68 to 0.95, p=0.01) and the 5/x plus x/x stratum did not (IRR 1.03, 95% CI 0.83 to 1.29, p=0.79), with an interaction p of 0.08 that does not itself reach conventional significance. The authors concluded there was no clear benefit, and that the genotype might identify a responsive subgroup. No genotype-directed prescribing followed.
Written into the record, not signed off as a reviewed claim
The harm is measurable, modest, and still not mechanistically explained
In plain words
Large matched-cohort studies do find more anxiety, mood and sleep diagnoses after starting montelukast. The size is one extra affected child in about sixty over a year, not a catastrophe — and nobody can say how the drug does it.
What was measured
That montelukast causes the neuropsychiatric diagnoses associated with it — supported by consistent direction across large matched cohorts and by the regulatory action, but without a demonstrated mechanism and without a randomised test
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
A propensity-matched cohort of 107,384 children and young people aged 3 to 17 with asthma, all on inhaled corticosteroids, found any neuropsychiatric outcome in 71 per 1,000 with adjunct montelukast against 54 per 1,000 without: RR 1.32 (95% CI 1.25 to 1.39), absolute risk increase 1.71 per 100 (95% CI 1.44 to 1.98), one-year number needed to harm 58 (95% CI 51 to 69). The largest excess was sleep disorders, RR 1.63 (95% CI 1.50 to 1.77). A companion propensity-matched cohort of 154,946 adults and adolescents aged 15 to 64 found odds ratios of 1.11 (95% CI 1.04 to 1.19) in asthma and 1.07 (95% CI 1.01 to 1.14) in allergic rhinitis. These are observational designs and confounding by indication is a live concern in both. The label is candid about the gap: it says the mechanisms underlying the events are currently not well understood, that based on available data it is difficult to identify risk factors or quantify the risk, and offers as its single mechanistic observation that animal studies showed montelukast distributes into the brain in rats.
Written into the record, not signed off as a reviewed claim
How many documents were read
68 documents were read for this substance.
RNAWiki source record
67 of them state the same volumeOfDistribution, and they agree.
RNAWiki source record
Where else this substance is registered
FDA substance identifier (UNII)
MHM278SD3E
CAS registry number
158966-92-8
PubChem compound
5281040
RxNorm concept
88249
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
✓ Passed
Safety mode resolved
Suppression classes recorded: S6.
✓ 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, 2018, for "Labeling: Label Mix-Up - One lot labeled Montelukast Sodium Tablets 10 mg tablets may contain 90 tablets of Losartan Potassium 50 mg." (openFDA drug enforcement Class I recall)
What the approval register records
52 approved applications cover products containing this substance. The earliest was NDA020830, approved 19980220 to ORGANON.
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 cysteinyl leukotriene receptor blocker that raised FEV1 by 13.0% against 4.2% on placebo in its pivotal asthma trial, carries a boxed warning for suicidal thoughts and behaviour added in March 2020 — twenty-two years after approval — and in the two hay fever trials on its own label that included an antihistamine comparator was beaten by loratadine and failed to separate from placebo where cetirizine did.
Recorded evidence blocks (11)
Q2
On the Montelukast label: indicated for what?
"1 INDICATIONS & USAGE Montelukast sodium tablets are a leukotriene receptor antagonist indicated for: Prophylaxis and chronic treatment of asthma in patients 15 years of age and older ( 1.1 ). Acute prevention of exercise-induced bronchoconstriction (EIB) in patients 15 years of age and older ( 1.2 ).": indications and usage on Montelukast's label. DailyMed label · 583a9499-97f0-2ebf-e063-6394a90a35af · 2026-08-04
Q3
260 registered trials of Montelukast — at which phases?
Registered studies posting no result
185 of 260
260 registered studies of Montelukast: 76 phase4, 65 phase3, 56 phase2, 33 phase1, 24 na, 10 early phase1, 9 na or unstated. CLINICALTRIALS_SNAPSHOT · 2026-09-01
638 with a PubMed record
Show the evidence
phase4
76
phase3
65
phase2
56
phase1
33
na
24
early phase1
10
9 more recorded rows
na or unstated
9
completed
186
unknown
32
recruiting
15
terminated
11
withdrawn
6
active not recruiting
5
not yet recruiting
4
suspended
1
recorded 2026-09-01 · last checked 2026-09-04
Q4
14 of Montelukast's trials stopped: accrual/recruitment, funding/business, other?
"Difficulty in recruitment"; 14 of 260 registered studies
Show the evidence
Trial
NCT00119015
terminated; "Difficulty in recruitment"
NCT00351364
terminated; "Diffic;ulty recruiting"
NCT00540839
withdrawn; "Based on input from regulatory agencies, it is not necessary to conduct this study. An ongoing study was sufficient for regulatory purposes."
NCT00599534
withdrawn; "Principal Investigator has transferred to another Institution"
NCT01016847
terminated; "Unable to enroll enough study subjects. Study has been terminated"
NCT01027806
terminated; "Poor accrual"
8 further recorded trials
NCT01224964
terminated; "A lot of patients recruited in our center were already on montelukast treatment. It was not possible to recruit sufficient patients for the study."
NCT01432080
terminated; "Not meeting recruitment targets"
NCT01458418
terminated; "Inability to complete enrollment due to difficulty in finding subjects"
NCT02655562
suspended; "There are difficulties in recruiting patients"
NCT03277170
withdrawn; "Unfunded"
NCT03545997
terminated; "lack of recruitment"
NCT04695704
terminated; "The incidence of respiratory Long COVID has decreased in the new waves, thus made impossible to achieve the required study sample."
NCT05362474
terminated; "Funding not available"
recorded 2026-09-01 · last checked 2026-09-04
Q5
Human studies of Montelukast used Singulair 10 mg — over how long?
studies of Montelukast used the recorded amount. ClinicalTrials.gov · 2026-09-01
20 recorded entries; human; tablet, orally; also "Singulair 10 mg", "montelukast (5mg QD)", "montelukast 10 mg tablet"
Show the evidence
human
NCT00252863
Singulair 10 mg
NCT00328718
montelukast (5mg QD)
NCT01007721
tablet; montelukast 10 mg tablet
NCT01086527
tablet; 10 mg tablet of montelukast (Singulair)
NCT01147744
Montelukast 10mg
NCT01458418
5 mg Montelukast
14 more recorded rows
humanNCT01615874
Montelukast tablets 5 mg (4 mg for children 5 years of age)
humanNCT01618929
Singulair 5 mg tablets
humanNCT01618929
Singulair 10 mg tablets
humanNCT01656395
Montelukast 10 mg
humanNCT01674517
Montelukast sodium chewable tablets 4mg and 5mg
humanNCT01863654
Montelukast 5 mg chewable tablets
humanNCT01928056
Torrent's Montelukast Sodium Tablets 10 mg
humanNCT02635334
orally; Montelukast 10 mg orally
humanNCT02761252
Placebo Montelukast 10mg
humanNCT03039101
Montelukast 10Mg Tablet
humanNCT03369119
Montelukast 4 Mg Oral Granule
humanNCT04198623
Montelukast 10 Mg Oral Tablet
humanNCT05293132
Montelukast Sodium 10 mg
humanNCT06887673
Montelukast 10 Mg Oral Tablet and SPM 4 g
recorded 2026-09-01 · last checked 2026-09-04
Q6
Montelukast's half-life is 2.7 to 5.5 hours — which schedules were studied?
2.7 to 5.5 hours; In several studies, the mean plasma half-life of montelukast ranged from 2.7 to 5.5 hours in healthy young adults.
tmaxpharmacokinetics
3 to 4 hours; After administration of the 10-mg film-coated tablet to fasted adults, the mean peak montelukast plasma concentration (C max ) is achieved in 3 to 4 hours (T max ).
bioavailabilitypharmacokinetics
64 %; The mean oral bioavailability is 64%.
metabolismpharmacokinetics
Metabolism Montelukast is extensively metabolized.
recorded 2026-08-04 · last checked 2026-09-04
Q7
Which running trial of Montelukast could settle inflammatory markers?
NCT07537868 measures Change in inflammatory biomarkers (IL-6, TNF-α, hs-CRP, Galectin-3, LTB4), reading out 2027-10.
1 open trial; n 80; "Effect of Montelukast on Inflammatory Markers and Cardiac Injury in Patients With Acute Myocardial Infarction"
Show the evidence
TrialNCT07537868
"Effect of Montelukast on Inflammatory Markers and Cardiac Injury in Patients With Acute Myocardial Infarction"; n 80; "Change in inflammatory biomarkers (IL-6, TNF-α, hs-CRP, Galectin-3, LTB4)"; 2027-10
Q8
Which 110 trials of Montelukast posted no result?
Posted no result
110 of 110 completed trials
Registrations
NCT00162864, NCT00700661, NCT00092092, NCT00756418, NCT01011452 and NCT00641472, and 104 more
Completion dates
oldest 2002-04; newest 2024-01-11
Show the evidence
Trial
NCT00162864
2002-04
NCT00700661
2002-12
NCT00092092
2004-06
NCT00756418
2004-08-28
NCT01011452
2004-10
NCT00641472
2005-02
14 further recorded trials
NCT00771160
2005-02
NCT00127647
2005-04
NCT00273013
2005-10-28
NCT00196547
2005-11
NCT00148408
2005-12
NCT00252863
2006-05
NCT01488773
2006-06
NCT00675285
2006-07
NCT00076973
2006-10
NCT00490243
2006-10
NCT00913328
2006-10
NCT00116324
2006-12
NCT00148603
2006-12
NCT00092989
2007-03
Q9
At the median, Montelukast's trials enrolled 79 people — anything larger?
Median enrolment
79
Largest enrolment
51533
Registered trials counted
258
Q10
What do 9505 spontaneous reports say about Montelukast — 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.
Montelukast appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 9505 reaction mentions were counted: asthma 2253; dyspnoea 1534; wheezing 1041; cough 879. FAERS via Open Targets · CHEMBL1200681 · 2026-06-24
Show the evidence
asthma
2253
dyspnoea
1534
wheezing
1041
cough
879
suicidal ideation
765
anxiety
664
4 more recorded rows
depression
660
therapeutic product effect incomplete
646
aggression
553
allergic granulomatous angiitis
510
recorded 2026-06-24 · last checked 2026-09-04
Q11
Which 10 reactions does Montelukast's label not list?
No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin, gemfibrozil, itraconazole, thyroid hormones, sedative hypnotics, non-steroidal anti-inflammatory agents, benzodiazepines, decongestants, and Cytochrome P450 (CYP) enzyme inducers [see Clinical Pharmacology ( 12.3 )].
pharmacokinetics
In vitro studies using human liver microsomes indicate that CYP3A4, 2C8, and 2C9 are involved in the metabolism of montelukast.
pharmacokinetics
Montelukast at a dose of 10 mg once daily dosed to pharmacokinetic steady state, did not cause clinically significant changes in the kinetics of a single intravenous dose of theophylline [predominantly a cytochrome P450 (CYP) 1A2 substrate].
pharmacokinetics
Montelukast at a dose of 10 mg once daily dosed to pharmacokinetic steady state did not change the plasma concentration profile of fexofenadine, did not change the pharmacokinetic profile or urinary excretion of immunoreactive digoxin; did not change the pharmacokinetic profile of warfarin (primarily a substrate of CYP2C9, 3A4 and 1A2) or influence the effect of a single 30-mg oral dose of…
pharmacokinetics
Cytochrome P450 (CYP) Enzyme Inducers Phenobarbital, which induces hepatic metabolism, decreased the area under the plasma concentration curve (AUC) of montelukast approximately 40% following a single 10-mg dose of montelukast.
pharmacokinetics
Effect of Montelukast on Cytochrome P450 (CYP) Enzymes: Montelukast is a potent inhibitor of CYP2C8 in vitro.
2 more recorded rows
Interaction statementpharmacokinetics
However, data from a clinical drug-drug interaction study involving montelukast and rosiglitazone (a probe substrate representative of drugs primarily metabolized by CYP2C8) in 12 healthy individuals demonstrated that the pharmacokinetics of rosiglitazone are not altered when the drugs are coadministered, indicating that montelukast does not inhibit CYP2C8 in vivo.
Interaction statementpharmacokinetics
Based on further in vitro results in human liver microsomes, therapeutic plasma concentrations of montelukast do not inhibit CYP 3A4, 2C9, 1A2, 2A6, 2C19, or 2D6.
Withdrawn in United States, 2018, for "Labeling: Label Mix-Up - One lot labeled Montelukast Sodium Tablets 10 mg tablets may contain 90 tablets of Losartan Potassium 50 mg." (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
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