Montelukast

Leukotriene receptor antagonists

ATC code: R03DC03

Updated 24 Sep 2026 · Methodology

Indications

Allergic rhinitis

Second line

Second-line for allergic rhinitis when antihistamines are insufficient. Less effective than intranasal corticosteroids. Per ARIA, may benefit patients with coexisting asthma and rhinitis – one drug addresses both conditions.

Sources

J Allergy Clin Immunol: Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines-2016 revision. (2017)
Am J Med: Leukotriene receptor antagonists for allergic rhinitis: a systematic review and meta-analysis. (2004)
Adv Ther: Montelukast in guidelines and beyond. (2009)
J Allergy Clin Immunol Pract: Intranasal Versus Oral Treatments for Allergic Rhinitis: A Systematic Review With Meta-Analysis. (2024)

ICD-10: J30.9 · ICD-11: CA08.0

Asthma

Adjunct

Add-on to ICS when asthma is uncontrolled at step 2. As add-on therapy, it is inferior to LABAs (formoterol, salmeterol) per meta-analyses. Preferred in patients with comorbid allergic rhinitis or aspirin-exacerbated respiratory disease, where the leukotriene component of inflammation is more prominent.

In children 6–14 years, montelukast may be considered an alternative to low-dose ICS when parents firmly refuse inhalers.

Sources

ICD-10: J45 · ICD-11: CA23

Exercise-induced bronchoconstriction

Second line

For exercise-induced bronchoconstriction the first-line is a short-acting bronchodilator (SABA) inhaled 5–20 minutes before exercise (ATS 2013, , GEMA). Montelukast is an add-on option for those with persistent symptoms and for patients whose asthma is mainly exercise-driven; its once-daily dosing protects for up to 24 hours. It acts more slowly and less strongly than a SABA, so it does not replace the inhaler right before exercise.

Sources

ICD-10: J45.9 · ICD-11: CA23.21

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Immune support and respiratory infection care

Not recommended

Montelukast is a leukotriene receptor antagonist. It is prescribed for asthma (as a first-line alternative) and allergic rhinitis ( 2024 guidelines). For shortness of breath or allergy prevention outside asthma or allergic rhinitis, montelukast is not used. In 2020 the added a boxed warning to the label about severe neuropsychiatric side effects: depression, anxiety, insomnia, nightmares, aggression, and suicidal thoughts and attempts. The FDA recommended avoiding montelukast for mild allergic rhinitis when other options are available (antihistamines, intranasal corticosteroids). If montelukast was prescribed for shortness of breath without confirmed asthma, consider seeking a second opinion, especially in children and adolescents.

Sources

How to read tiers A–F

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit

Mechanism of action

Selective CysLT1 receptor antagonist. Blocks leukotriene D4 activity in the airways – a mediator responsible for bronchoconstriction, mucosal edema, mucus secretion, and eosinophil recruitment. Taken orally once daily.

Safety

Boxed warning

FDA black box (2020): serious neuropsychiatric events including suicidal thoughts and actions, depression, agitation, aggression, and sleep disturbances, including in children. Prescribers must weigh benefits and risks. Patients and caregivers are instructed to seek immediate medical attention for behavioral or mood changes.

Contraindications

Hypersensitivity to montelukast or any component

Serious adverse effects

Neuropsychiatric events – aggression, anxiety, depression, suicidal ideation (FDA black box)
Churg-Strauss syndrome (eosinophilic granulomatosis with polyangiitis) – rare, when corticosteroid dose is reduced
Angioedema (isolated cases)

Common adverse effects

Headache
Abdominal pain
Diarrhea
Upper respiratory infections (in pediatric trials)

Pregnancy: can you take Montelukast?

AEMPS summary of product characteristics (section 4.6): animal studies do not indicate harmful effects on pregnancy or embryo-fetal development. Limited data from available pregnancy databases do not suggest a causal link between montelukast and malformations (for example, limb defects), which have been rarely reported in worldwide post-marketing experience. Montelukast may be used in pregnancy only if clearly necessary.

Breastfeeding: can you take Montelukast?

Compatible. Hale L3. Transfers into milk in small amounts; RID about 0.7–3%. Observational data do not document clinical problems in breastfed infants. The 2020 AEMPS alert on neuropsychiatric reactions (behavioural change, depression, self-harm ideation) refers to the patient taking the drug, not to infants exposed through milk. Mild infant irritability or sleep disturbance is possible but rare and usually self-limited.

Calculate RID Full profile on NIH LactMed ↗

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Practical notes

Timing and administration

For asthma – 10 mg in the evening (adults). Evening dosing was used in pivotal trials; changing the time is not recommended. For exercise-induced bronchoconstriction – take 2 hours before exercise. If the patient already takes montelukast nightly, no extra dose is needed before exercise.

Monitoring

No routine laboratory monitoring is required. Neuropsychiatric symptoms must be monitored – mood changes, aggression, sleep disturbance, suicidal ideation. In 2020, the added a black box warning requiring that patients and parents be informed. The drug is discontinued if such symptoms appear.

Drug–drug interactions

1 pair found. Sorted from critical to minor.

MinorAmiodaroneClass III antiarrhythmics (Vaughan Williams)

Mechanism

No clinically significant direct interaction. Montelukast is metabolised by CYP2C8 and CYP3A4; amiodarone moderately inhibits CYP3A4. Montelukast AUC may rise slightly, without clinical consequences.

Symptoms

The combination usually causes no specific symptoms. Each drug's individual side effects remain.

Management

No dose adjustment needed. In asthma with atrial fibrillation, the combination is standard.

Sources

FDA: Amiodarone hydrochloride tablet (Dr. Reddy's Labratories Inc.) – Prescribing Information (2018)

Pair details →Amiodarone →

Label mentions30 mentions

Verbatim lines from the interaction sections, in the language of the label

From this drug’s label

ModerateGemfibrozil
«Estudios in vitro han demostrado que montelukast es un sustrato de CYP 2C8, y en menor medida, de 2C9 y 3A4. En un estudio de interacción farmacológica que incluía montelukast y gemfibrozilo (un…»
AEMPS, section 4.5 · Open on CIMA
anticonceptivos hormonalesclass named in the label
«Montelukast puede administrarse junto con otros tratamientos utilizados sistemáticamente en la profilaxis y el tratamiento crónico del asma. En estudios de interacciones farmacológicas, la dosis…»
AEMPS, section 4.5 · Open on CIMA
benzodiazepinesclass named in the label
«DRUG INTERACTIONS: No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin…»
FDA, section 7 · Open on DailyMed
Digoxin
«Montelukast puede administrarse junto con otros tratamientos utilizados sistemáticamente en la profilaxis y el tratamiento crónico del asma. En estudios de interacciones farmacológicas, la dosis…»
AEMPS, section 4.5 · Open on CIMA
Digoxin
«DRUG INTERACTIONS: No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin…»
FDA, section 7 · Open on DailyMed
Estradiol
«Montelukast puede administrarse junto con otros tratamientos utilizados sistemáticamente en la profilaxis y el tratamiento crónico del asma. En estudios de interacciones farmacológicas, la dosis…»
AEMPS, section 4.5 · Open on CIMA
Fexofenadine
«DRUG INTERACTIONS: No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin…»
FDA, section 7 · Open on DailyMed
Gemfibrozil
«DRUG INTERACTIONS: No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin…»
FDA, section 7 · Open on DailyMed
hormonal contraceptivesclass named in the label
«DRUG INTERACTIONS: No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin…»
FDA, section 7 · Open on DailyMed
inductores del CYP3A4class named in the label
«El área bajo la curva de concentración plasmática (AUC) de montelukast disminuyó aproximadamente en un 40 % en pacientes que recibían simultáneamente fenobarbital. Puesto que montelukast se…»
AEMPS, section 4.5 · Open on CIMA
Itraconazole
«En base a los datos in vitro , no se esperan interacciones medicamentosas clínicamente importantes con inhibidores menos potentes de CYP 2C8 (p. ej., trimetoprim). La administración conjunta de…»
AEMPS, section 4.5 · Open on CIMA
Itraconazole
«DRUG INTERACTIONS: No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin…»
FDA, section 7 · Open on DailyMed
Phenobarbital
«El área bajo la curva de concentración plasmática (AUC) de montelukast disminuyó aproximadamente en un 40 % en pacientes que recibían simultáneamente fenobarbital. Puesto que montelukast se…»
AEMPS, section 4.5 · Open on CIMA
Phenytoin
«El área bajo la curva de concentración plasmática (AUC) de montelukast disminuyó aproximadamente en un 40 % en pacientes que recibían simultáneamente fenobarbital. Puesto que montelukast se…»
AEMPS, section 4.5 · Open on CIMA
Prednisolone
«Montelukast puede administrarse junto con otros tratamientos utilizados sistemáticamente en la profilaxis y el tratamiento crónico del asma. En estudios de interacciones farmacológicas, la dosis…»
AEMPS, section 4.5 · Open on CIMA
Prednisolone
«DRUG INTERACTIONS: No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin…»
FDA, section 7 · Open on DailyMed
Prednisone
«Montelukast puede administrarse junto con otros tratamientos utilizados sistemáticamente en la profilaxis y el tratamiento crónico del asma. En estudios de interacciones farmacológicas, la dosis…»
AEMPS, section 4.5 · Open on CIMA
Prednisone
«DRUG INTERACTIONS: No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin…»
FDA, section 7 · Open on DailyMed
Repaglinide
«Estudios in vitro han demostrado que montelukast es un inhibidor potente de CYP 2C8. Sin embargo, datos procedentes de un ensayo clínico de interacción farmacológica que incluía a montelukast y…»
AEMPS, section 4.5 · Open on CIMA
Rifampicin
«El área bajo la curva de concentración plasmática (AUC) de montelukast disminuyó aproximadamente en un 40 % en pacientes que recibían simultáneamente fenobarbital. Puesto que montelukast se…»
AEMPS, section 4.5 · Open on CIMA
Theophylline
«Montelukast puede administrarse junto con otros tratamientos utilizados sistemáticamente en la profilaxis y el tratamiento crónico del asma. En estudios de interacciones farmacológicas, la dosis…»
AEMPS, section 4.5 · Open on CIMA
Theophylline
«DRUG INTERACTIONS: No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin…»
FDA, section 7 · Open on DailyMed
Trimethoprim
«En base a los datos in vitro , no se esperan interacciones medicamentosas clínicamente importantes con inhibidores menos potentes de CYP 2C8 (p. ej., trimetoprim). La administración conjunta de…»
AEMPS, section 4.5 · Open on CIMA
Warfarin
«Montelukast puede administrarse junto con otros tratamientos utilizados sistemáticamente en la profilaxis y el tratamiento crónico del asma. En estudios de interacciones farmacológicas, la dosis…»
AEMPS, section 4.5 · Open on CIMA
Warfarin
«DRUG INTERACTIONS: No dose adjustment is needed when montelukast sodium is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin…»
FDA, section 7 · Open on DailyMed

From other drugs’ labels

ModerateGemfibrozil
«El perfil de interacciones de gemfibrozilo es complejo. Los estudios in vivo indican que gemfibrozilo y su metabolito gemfibrozilo 1-O-β-glucurónido son potentes inhibidores de CYP2C8 (un enzima…»
AEMPS, section 4.5 · Open on CIMA
Phenobarbital
«Montelukast : posible disminución de la eficacia de montelukast.»
AEMPS, section 4.5 · Open on CIMA
Repaglinide
«DRUG INTERACTIONS: Examples: Drugs that are known to inhibit CYP3A4 include antifungal agents (ketoconazole, itraconazole) and antibacterial agents (clarithromycin, erythromycin). Drugs that are…»
FDA, section 7 · Open on DailyMed
Roflumilast
«No se han observado interacciones con salbutamol, formoterol y budesónida por vía inhalada, ni con montelukast, digoxina, warfarina, sildenafilo y midazolam por vía oral.»
AEMPS, section 4.5 · Open on CIMA
Warfarin
«CYP450 Interactions: CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives…»
FDA, section 7 · Open on DailyMed

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Frequently asked

What is Montelukast used for?

Montelukast is evaluated for the following indications with varying evidence strength: Exercise-induced bronchoconstriction (evidence tier B), Allergic rhinitis (evidence tier B), Asthma (evidence tier B). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Montelukast?

Common side effects of Montelukast (≥ 1 in 100): Headache, Abdominal pain, Diarrhea, Upper respiratory infections (in pediatric trials). See the Safety section for uncommon and serious reactions.

Is Montelukast safe during pregnancy?

Is Montelukast compatible with breastfeeding?

Who should not take Montelukast?

Montelukast is contraindicated in: Hypersensitivity to montelukast or any component. Full list in the Safety section.

Does Montelukast carry an FDA boxed warning?

Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMA
FDA / DailyMedLabel dated 05/30/2025

Other drugs in this group

Roflumilast, Salbutamol (Albuterol), Salmeterol, Salmeterol + Fluticasone, Tiotropium, Budesonide, Fluticasone propionate, Theophylline