MVIIIHealth The MVIII app
← Back

Research · Medication

Montelukast

Trials found montelukast improved lung function and asthma symptoms against placebo, but left more exacerbations than an inhaled steroid or an added long-acting bronchodilator. It relieved hay fever symptoms modestly. FDA added a boxed warning in 2020 for serious mood and behavior changes, while pooled placebo-controlled trials found behavior events in 2.73% against 2.27%.

Add to Bio HackChecked 2026-11-13
Status
Prescription drug in the US, approved for long-term asthma treatment from 12 months of age, prevention of exercise-induced bronchoconstriction from age 6, and seasonal and perennial allergic rhinitis. The label carries an FDA boxed warning on serious neuropsychiatric events and reserves allergic rhinitis use for people who did not respond to or could not take other treatments.
Also called
Singulair, montelukast sodium, leukotriene receptor antagonist, LTRA, leukotriene blocker, anti-leukotriene
Taken for
asthma, exercise-induced asthma, hay fever, allergic rhinitis, chronic hives, snoring and sleep apnea in children, add-on to inhaled steroids

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help5

Reported risks4

What people take it for, and what was found

Shown to help5

Moderate

Asthma, against placebo

Shown to improve lung function, daytime symptoms and night waking against placebo in mild to moderate asthma, with FEV1 up 0.22 L more than placebo in one trial.

Compared with placebo [1]

The numbers and sources
Effect
Over 12 weeks, FEV1 rose 13.0% on montelukast 10 mg and 4.2% on placebo, a difference of 0.22 L (95% CI 0.17 to 0.27). In the second trial, daytime symptom scores fell 0.49 against 0.26, rescue inhaler use fell 1.65 against 0.42 puffs a day, and night waking fell 2.03 against 0.78 times a week [1].
Population
1,576 adults and adolescents aged 15 and older with mild or moderate asthma in two 12-week trials, 795 on montelukast and 530 on placebo [1].
Sources
[1]
Caveats
Label trials. Doses above 10 mg a day gave no added benefit [1].
Moderate

Asthma, added to an inhaled steroid

Shown to halve exacerbations needing oral steroids when added to an inhaled steroid in adults and adolescents, about 22 treated for one fewer exacerbation.

Compared with the same dose of inhaled steroid alone [3]

The numbers and sources
Effect
Adding an anti-leukotriene to the same inhaled steroid dose halved the number of people with exacerbations needing oral steroids (RR 0.50, 95% CI 0.29 to 0.86), a number needed to treat of 22 over 6 to 16 weeks. All adverse events did not differ (RR 1.06) [3].
Population
6,128 adults and adolescents in 37 studies, 24 of montelukast; 815 people in the 4 studies of the main outcome [3].
Sources
[3]
Caveats
Moderate-quality evidence from few studies for the main outcome. Zafirlukast and pranlukast trials are included [3].
Moderate

Exercise-induced airway narrowing

Shown to reduce the drop in lung function after exercise when taken 2 hours before, a 13% fall against 22% on placebo, with less protection at 24 hours.

Compared with placebo [1]

The numbers and sources
Effect
In one crossover trial, the mean maximum fall in FEV1 after exercise 2 hours after a 10 mg dose was 13% on montelukast and 22% on placebo (difference -9%, 95% CI -12 to -5). At 24 hours the falls were 10% and 14%. Some patients were protected at 8.5 and 24 hours and some were not [1].
Population
160 people aged 15 and older with exercise-induced bronchoconstriction in three crossover trials, 47 in the trial reported [1].
Sources
[1]
Caveats
Label trials with single doses. The label reports the other two trials as similar [1].
Moderate

Hay fever (seasonal allergic rhinitis)

Shown to improve hay fever symptoms modestly against placebo, about 5% more, slightly less than antihistamines and less than nasal steroid sprays.

Compared with placebo [5]; antihistamines [5]; nasal corticosteroids [5]

The numbers and sources
Effect
Leukotriene receptor antagonists lowered daily rhinitis symptom scores 5% (95% CI 3% to 7%) more than placebo and improved rhinoconjunctivitis quality of life by 0.3 units. Antihistamines improved nasal symptoms 2% (95% CI 0% to 4%) more, and nasal corticosteroids 12% (95% CI 5% to 18%) more, than leukotriene receptor antagonists [5].
Population
8 trials with 3,924 people with seasonal allergic rhinitis [5].
Sources
[5]
Caveats
No randomized trials of perennial rhinitis were found in this review [5]. The label reserves rhinitis use for people who did not respond to or could not take other treatments [1].
LimitedStudied in children

Sleep apnea and snoring in children

Small trials found montelukast improved sleep study measures, snoring and mouth breathing in children with mild to moderate obstructive sleep apnea over short periods.

Compared with placebo [7]; nasal mometasone alone [7]

The numbers and sources
Effect
Against placebo, oral montelukast improved polysomnography measures, snoring, mouth breathing and adenoid size. Added to mometasone nasal spray, it improved sleep study measures and snoring more than the spray alone [7].
Population
305 children with mild to moderate obstructive sleep apnea in 4 randomized trials [7].
Sources
[7]
Caveats
Four small short-term trials. The abstract gives no effect sizes [7].

Mixed results1

Limited

Chronic hives

Limited evidence: most trials found leukotriene blockers alone no better than placebo or antihistamines for chronic hives, while adding one to an antihistamine appeared to help more.

Compared with placebo or antihistamines [6]

The numbers and sources
Effect
Across 10 randomized trials, most found leukotriene receptor antagonists not superior to placebo or antihistamines as monotherapy, while the combination with antihistamines appeared to improve hives more than antihistamines alone. Heterogeneity was too high for a pooled analysis [6].
Population
10 randomized or crossover trials in chronic urticaria [6].
Sources
[6]
Caveats
No pooled estimate. Trials differed in design and outcomes [6].

Not shown to help2

Moderate

Asthma, montelukast alone against an inhaled steroid

Shown to leave more asthma exacerbations needing oral steroids than an inhaled steroid, one extra exacerbation for every 28 people treated with montelukast instead.

Compared with inhaled corticosteroids [2]

The numbers and sources
Effect
People treated with an anti-leukotriene instead of an inhaled steroid were more likely to have an exacerbation needing oral steroids (RR 1.51, 95% CI 1.17 to 1.96), one more for every 28 treated (95% CI 15 to 82). The gap was larger with moderate airway obstruction (RR 2.03) than mild (RR 1.25) [2].
Population
10,005 adults and 3,333 children with mild or moderate persistent asthma in 56 trials of 4 to 52 weeks [2].
Sources
[2]
Caveats
The inhaled steroid dose was about 200 µg a day of beclomethasone or equivalent. The review covers anti-leukotrienes as a group [2].
Moderate

Added to an inhaled steroid, against an added long-acting beta-agonist

Shown to leave slightly more exacerbations than adding a long-acting beta-agonist to an inhaled steroid, 13% against 11%.

Compared with a long-acting beta-agonist added to the inhaled steroid [4]

The numbers and sources
Effect
Exacerbations needing oral steroids were 13% with an anti-leukotriene plus inhaled steroid and 11% with a long-acting beta-agonist plus inhaled steroid (RR 0.87, 95% CI 0.76 to 0.99 favoring the beta-agonist), one fewer for every 62 treated. Lung function, symptoms and rescue use also favored the beta-agonist [4].
Population
7,208 participants in 18 trials, 336 of them children aged 6 to 17 [4].
Sources
[4]
Caveats
High-quality evidence. The choice of anti-leukotriene did not change the result [4].

Doses studied

The label lists one 10 mg tablet in the evening from age 15, a 5 mg chewable tablet at ages 6 to 14, and 4 mg chewable tablets or granules at ages 2 to 5, with 4 mg granules down to 6 or 12 months by use. For exercise, a single dose at least 2 hours before exercise. The label trials used 10 mg once daily, and doses above 10 mg gave no added benefit [1].

Risks

Reported risks3

ModerateVery common

Headache, stomach upset and other common side effects

Shown in label trials to cause side effects at rates close to placebo, with headache in 18.4% on montelukast against 18.1% on placebo.

The numbers and sources
How common
Very common: more than 1 in 10 people.
Effect
In adult and adolescent asthma trials, rates on montelukast 10 mg and placebo were headache 18.4% and 18.1%, influenza 4.2% and 3.9%, abdominal pain 2.9% and 2.5%, dyspepsia 2.1% and 1.1%, dizziness 1.9% and 1.4%, and raised ALT 2.1% and 2.0% [1].
Population
1,955 people on montelukast and 1,180 on placebo aged 15 and older [1].
Sources
[1]
Caveats
The label lists events regardless of cause, and most differ little from placebo [1].
LimitedHow often is not known

FDA boxed warning: serious neuropsychiatric events

FDA states serious neuropsychiatric events, including agitation, aggression, depression, sleep disturbances and suicidal thoughts and behavior, have been reported with montelukast. The label gives no rate.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
The boxed warning lists agitation, aggression, depression, sleep disturbances, and suicidal thoughts and behavior including suicide, and states the mechanism is not well understood. The label lists further reported events including hallucinations, memory impairment, stuttering, sleepwalking and tics, in people with and without a psychiatric history, some after stopping [1]. FDA required the boxed warning in March 2020 after reviewing case reports, including 82 reported completed suicides, most of which (48 of 82) lacked enough information to judge whether montelukast was involved, and an observational study in its Sentinel system that did not find an increased risk compared with inhaled corticosteroids [8].
Population
Postmarketing reports in children, adolescents and adults [1][8].
Sources
[1], [8]
Caveats
Spontaneous reports cannot give a rate or prove cause. FDA's own observational study did not find a higher risk [8].
LimitedHow often is not known

Eosinophilia and Churg-Strauss vasculitis

The label reports systemic eosinophilia, sometimes with vasculitis consistent with Churg-Strauss syndrome, often as oral steroids were reduced. A causal link has not been established.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
The label states people with asthma on montelukast may present with systemic eosinophilia, sometimes with vasculitis consistent with Churg-Strauss syndrome, sometimes associated with reducing oral corticosteroids. It states a causal association has not been established [1].
Population
Postmarketing reports summarized in labeling [1].
Sources
[1]
Caveats
Reducing oral steroids may unmask the underlying condition [1].

Mixed results1

ModerateCommon

Mood and behavior changes in trials and cohort studies

Mixed results: pooled placebo-controlled trials found behavior events in 2.73% on montelukast against 2.27% on placebo, while some observational studies linked it to anxiety, ADHD and other events.

The numbers and sources
How common
Common: between 1 in 100 and 1 in 10 people.
Effect
In 46 placebo-controlled trials, behavior-related adverse events occurred in 2.73% on montelukast and 2.27% on placebo (OR 1.12, 95% CI 0.93 to 1.36), and serious ones in 0.03% of each [9]. A meta-analysis of 18 randomized trials found no significant rise in neuropsychiatric events against placebo [10]. A 2025 meta-analysis found 11% higher risk of anxiety (RR 1.11, 95% CI 1.06 to 1.16) and no consistent rise in depression or suicidal behavior [11]. In children with asthma, one case-control study found new neuropsychiatric events at nearly twice the odds with montelukast (OR 1.91, 95% CI 1.15 to 3.18) [12], another found no association (adjusted OR 1.01, 95% CI 0.88 to 1.14) [13], and a birth cohort linked it to ADHD (HR 1.40) and conduct disorders (HR 1.43) against inhaled steroids [14].
Population
11,673 people on montelukast and 8,827 on placebo [9]; 18 randomized trials [10]; 4 studies for the mental health analysis [11]; 898 cases and 3,497 controls [12]; 1,920 cases [13]; 97,176 children with asthma in two cohorts [14].
Sources
[9], [10], [11], [12], [13], [14]
Caveats
The trial analysis counted events reported as adverse experiences, which can miss milder changes [9]. Observational studies can be confounded by asthma severity and by who is prescribed montelukast.

Checked, no increase found1

LimitedStudied in pregnancy

Pregnancy

The label states cohort studies over decades have not established a risk of major birth defects with montelukast. Animal studies at about 100 times human exposure found no developmental harm.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
The label states published prospective and retrospective cohort studies have not identified an association with major birth defects, while noting small samples and inconsistent comparator groups. Rats and rabbits showed no adverse developmental effects at about 100 and 110 times the human exposure [1].
Population
Pregnancy cohorts and animal studies summarized in labeling [1].
Sources
[1]
Caveats
Observational studies with methodological limits [1].

Claims tested and not found

  1. That montelukast raises mood and behavior events in placebo-controlled trials. Behavior-related events were 2.73% on montelukast and 2.27% on placebo (OR 1.12, 95% CI 0.93 to 1.36) [9], and a meta-analysis of 18 randomized trials found no significant increase [10].
  2. That montelukast controls asthma as well as an inhaled steroid. Exacerbations needing oral steroids were more likely on an anti-leukotriene (RR 1.51, 95% CI 1.17 to 1.96) [2].

Sources

  1. U.S. Food and Drug Administration. SINGULAIR (montelukast sodium) tablets, chewable tablets and oral granules, prescribing information. 2025. DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=482dcc92-b47f-4ea6-854a-f5ac2aea7842
  2. Chauhan BF, Ducharme FM. Anti-leukotriene agents compared to inhaled corticosteroids in the management of recurrent and/or chronic asthma in adults and children. Cochrane Database of Systematic Reviews. 2012. https://doi.org/10.1002/14651858.CD002314.pub3
  3. Chauhan BF, Jeyaraman MM, Singh Mann A, et al. Addition of anti-leukotriene agents to inhaled corticosteroids for adults and adolescents with persistent asthma. Cochrane Database of Systematic Reviews. 2017. https://doi.org/10.1002/14651858.CD010347.pub2
  4. Chauhan BF, Ducharme FM. Addition to inhaled corticosteroids of long-acting beta2-agonists versus anti-leukotrienes for chronic asthma. Cochrane Database of Systematic Reviews. 2014. https://doi.org/10.1002/14651858.CD003137.pub5
  5. Wilson AM, O'Byrne PM, Parameswaran K. Leukotriene receptor antagonists for allergic rhinitis: a systematic review and meta-analysis. American Journal of Medicine. 2004. https://doi.org/10.1016/j.amjmed.2003.10.030
  6. de Silva NL, Damayanthi H, Rajapakse AC, et al. Leukotriene receptor antagonists for chronic urticaria: a systematic review. Allergy, Asthma & Clinical Immunology. 2014. https://doi.org/10.1186/1710-1492-10-24
  7. Ji T, Lu T, Qiu Y, et al. The efficacy and safety of montelukast in children with obstructive sleep apnea: a systematic review and meta-analysis. Sleep Medicine. 2021. https://doi.org/10.1016/j.sleep.2020.11.009
  8. U.S. Food and Drug Administration. FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Singulair); advises restricting use for allergic rhinitis. Drug Safety Communication. 2020. https://www.fda.gov/drugs/drug-safety-communications/fda-requires-boxed-warning-about-serious-mental-health-side-effects-asthma-and-allergy-drug
  9. Philip G, Hustad CM, Malice MP, et al. Analysis of behavior-related adverse experiences in clinical trials of montelukast. Journal of Allergy and Clinical Immunology. 2009. https://doi.org/10.1016/j.jaci.2009.08.011
  10. Mou Y, Song Q, Zhao C, et al. Meta-analysis of the relationship between montelukast use and neuropsychiatric events in patients with allergic airway disease. Heliyon. 2023. https://doi.org/10.1016/j.heliyon.2023.e21842
  11. Sobczak M, Pawliczak R. Montelukast: risk of mental disorders vs. efficacy-a meta-analysis. Frontiers in Pharmacology. 2025. https://doi.org/10.3389/fphar.2025.1659852
  12. Glockler-Lauf SD, Finkelstein Y, Zhu J, et al. Montelukast and Neuropsychiatric Events in Children with Asthma: A Nested Case-Control Study. Journal of Pediatrics. 2019. https://doi.org/10.1016/j.jpeds.2019.02.009
  13. Ali MM, O'Brien CE, Cleves MA, et al. Exploring the possible association between montelukast and neuropsychiatric events among children with asthma: a matched nested case-control study. Pharmacoepidemiology and Drug Safety. 2015. https://doi.org/10.1002/pds.3758
  14. Jiao XF, Ducharme FM, Leal LF, et al. Neuropsychiatric outcomes after montelukast versus inhaled corticosteroids in pediatric asthma: a pooled birth cohort study. BMC Medicine. 2026. https://doi.org/10.1186/s12916-026-05235-7

Everything in the library