Formulary
Montelukast: Uses, Dosing, Side Effects and Indian Brand Names
Montelukast blocks CysLT1 receptors, reducing leukotriene-mediated bronchoconstriction, inflammation, and mucus secretion. It is used as an add-on controller in asthma and is especially effective in exercise-induced asthma and aspirin-exacerbated respiratory disease.
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Montelukast: Uses, Dosing, Side Effects and Indian Brand Names
Montelukast blocks CysLT1 receptors, reducing leukotriene-mediated bronchoconstriction, inflammation, and mucus secretion. It is used as an add-on controller in asthma and is especially effective in exercise-induced asthma and aspirin-exacerbated respiratory disease.
NEET PG High-Yield: Montelukast blocks CysLT1 receptors (leukotriene pathway -- NOT COX pathway). Best for exercise-induced asthma and aspirin-exacerbated respiratory disease (AERD/Samter's triad). NOT a rescue drug -- does not work acutely. Oral once-daily dosing (compliance advantage in children). The 5-lipoxygenase inhibitor is zileuton (not available in India), which blocks leukotriene synthesis (upstream of montelukast).
Clinical overview
Montelukast is the most widely used leukotriene receptor antagonist and plays a significant role in asthma management, particularly in step 2-3 therapy per GINA guidelines (as an add-on to inhaled corticosteroids or as an alternative controller in mild persistent asthma when ICS is refused or not tolerated). It is especially useful in specific asthma phenotypes: exercise-induced asthma, aspirin-exacerbated respiratory disease (AERD/Samter's triad), and asthma with coexisting allergic rhinitis (leukotrienes mediate symptoms in both conditions, making montelukast a single drug for dual benefit). Unlike inhaled corticosteroids, montelukast is an oral tablet taken once daily at bedtime, which offers a significant compliance advantage, especially in paediatric patients. In India, montelukast is widely prescribed for asthma and allergic rhinitis, often in fixed-dose combinations with fexofenadine or levocetirizine. The FDA issued a black box warning in 2020 regarding neuropsychiatric side effects (mood changes, suicidal ideation, sleep disturbances, behavioural changes), particularly in children and adolescents. This has led to a recommendation that montelukast should only be used in patients who have not responded adequately to other therapies or in whom the benefit clearly outweighs the neuropsychiatric risk.
Pharmacological class
Montelukast belongs to the Leukotriene receptor antagonist (LTRA; cysteinyl leukotriene-1 receptor antagonist) class. Montelukast selectively blocks the cysteinyl leukotriene-1 (CysLT1) receptor, preventing the actions of leukotrienes C4, D4, and E4. These leukotrienes are potent inflammatory mediators produced by the 5-lipoxygenase pathway from arachidonic acid. They cause bronchoconstriction (1000 times more potent than histamine), increased vascular permeability, mucus hypersecretion, and eosinophil recruitment in the airways. By blocking CysLT1 receptors, montelukast reduces all these effects.
Indian brand names and formulations
Available as: Montair (Cipla), Montek (Sun Pharma), Singulair (MSD/Organon), Romilast (Glenmark Pharmaceuticals).
Film-coated tablets (10 mg), Chewable tablets (4 mg, 5 mg), Oral granules (4 mg sachet for infants/toddlers), Fixed-dose combinations with antihistamines (montelukast + levocetirizine, montelukast + fexofenadine)
Regulatory status
Montelukast is classified under Schedule H in India under the Drugs and Cosmetics Act, 1940. Schedule H prescription drug. FDA black box warning (2020) for neuropsychiatric adverse events. Should be used only after considering the benefit-risk balance, especially in children.
Indications
- Asthma (add-on controller, step 2-3; alternative to low-dose ICS in mild persistent asthma)
- Exercise-induced bronchoconstriction (prophylaxis)
- Aspirin-exacerbated respiratory disease (AERD/Samter's triad)
- Allergic rhinitis (seasonal and perennial)
- Asthma with coexisting allergic rhinitis (dual benefit)
Dosing
Adults and adolescents (>15 years): 10 mg once daily at bedtime. Children 6-14 years: 5 mg chewable tablet at bedtime. Children 2-5 years: 4 mg chewable tablet/granules at bedtime. Children 6 months-2 years: 4 mg granules at bedtime. Exercise-induced: 10 mg at least 2 hours before exercise. No dose adjustment for renal or mild-moderate hepatic impairment.
Contraindications
- Known hypersensitivity to montelukast
- Not for acute bronchospasm rescue (does not provide rapid bronchodilation)
- Churg-Strauss syndrome (eosinophilic granulomatosis with polyangiitis) -- cases reported during corticosteroid tapering in patients started on montelukast (causal vs unmasking debated)
Adverse effects
- Headache (most common in adults)
- Neuropsychiatric effects: agitation, aggression, mood changes, sleep disturbances, nightmares, depression, suicidal ideation (FDA black box warning)
- Upper respiratory tract infection (in clinical trials -- common in paediatric population regardless of treatment)
- GI disturbance (abdominal pain, diarrhoea)
- Elevated liver transaminases (rare)
- Allergic reactions including anaphylaxis (rare)
- Churg-Strauss syndrome (rare, temporal association)
Drug interactions
- CYP3A4 inducers (phenytoin, rifampicin, phenobarbital) -- may reduce montelukast levels (limited clinical significance)
- CYP2C8 inhibitors (gemfibrozil) -- increase montelukast levels approximately 4-fold
- No clinically significant interactions with inhaled corticosteroids, SABAs, or antihistamines (commonly co-prescribed safely)
Pregnancy and lactation
Category B. Limited human data, but no signal of teratogenicity in available studies and registries. The general recommendation is to continue montelukast during pregnancy if it was effective before pregnancy and asthma control requires it. Uncontrolled asthma poses a greater risk to the fetus than montelukast.
Exam-style clinical scenario
A 30-year-old woman with a history of nasal polyps and asthma develops severe bronchospasm 30 minutes after taking aspirin for a headache. After stabilisation, she asks about long-term management. What is the role of montelukast? Answer: This is aspirin-exacerbated respiratory disease (AERD/Samter's triad): asthma + nasal polyposis + aspirin/NSAID sensitivity. The pathophysiology involves overproduction of cysteinyl leukotrienes (due to constitutive overactivity of the 5-lipoxygenase pathway), which is amplified by COX-1 inhibition. Montelukast, by blocking CysLT1 receptors, directly addresses the pathogenic mechanism. It is particularly effective in AERD patients and is recommended as add-on therapy alongside intranasal corticosteroids and ICS.
Cost in India
INR 80-130 per strip of 10 tablets (10 mg); FDC with levocetirizine: INR 100-160 per strip
Clinical governance
Author: MedNext Editorial Team. Clinical reviewer: Awaiting clinical review. Jurisdiction: India (Drugs and Cosmetics Act, 1940). Sources: CIMS India, Indian Pharmacopoeia. Publication state: Awaiting clinical review. Correction: Report errors at support@mednext.academy.
Frequently Asked Questions
Why is montelukast particularly effective in aspirin-exacerbated respiratory disease?
In AERD, there is constitutive overexpression of 5-lipoxygenase and leukotriene C4 synthase, leading to overproduction of cysteinyl leukotrienes. COX-1 inhibition by aspirin/NSAIDs diverts even more arachidonic acid toward the lipoxygenase pathway, further increasing leukotriene levels. Montelukast blocks the downstream CysLT1 receptor, directly addressing the excess leukotriene signalling. Studies show 60-80% of AERD patients improve on montelukast.
What is the FDA black box warning about montelukast?
In March 2020, the FDA required a black box warning (their most prominent safety warning) for serious mental health side effects: agitation, depression, sleeping problems, suicidal thoughts and actions. These are reported more frequently in children and adolescents. The FDA advised healthcare professionals to consider the benefits and risks of montelukast, inform patients about these potential effects, and avoid prescribing it for allergic rhinitis if other appropriate therapies are available.
Can montelukast replace inhaled corticosteroids in asthma?
No, montelukast should not routinely replace ICS. Inhaled corticosteroids remain the cornerstone of asthma controller therapy and are more effective than montelukast as monotherapy for most asthma patients. Montelukast is positioned as: (1) an alternative to low-dose ICS only if ICS is refused or not tolerated, (2) add-on therapy to ICS for better control, or (3) preferred in specific phenotypes (exercise-induced, AERD). GINA 2023 guidelines place greater emphasis on ICS-containing therapy.
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