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Montelukast

Montelukast

Singulair Montair Lukair Monteflo Montelo-10

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Updated: December 06, 2025

Overview

Montelukast is a leukotriene receptor antagonist (LTRA) used primarily in the management of asthma and allergic rhinitis. It works by blocking the action of leukotrienes, inflammatory mediators that cause airway constriction, swelling, and mucus production. The drug is particularly effective for prophylaxis and chronic treatment but is not intended for acute asthma attacks. Montelukast is well-tolerated in most patients and available in oral formulations. It has a favorable safety profile, though rare neuropsychiatric adverse effects have been reported. The drug is approved for use in adults and children as young as 6 months for certain indications.

Drug Class

Selective, competitive cysteinyl leukotriene receptor antagonist (CysLT1) Therapeutic category: Anti-asthmatic, Antiallergic

Mechanism of Action

• Competitively blocks cysteinyl leukotriene type 1 (CysLT1) receptors • Inhibits physiological actions of leukotriene D4 (LTD4) • Reduces airway eosinophilic inflammation • Decreases vascular permeability and mucus secretion • Prevents bronchoconstriction induced by inflammatory stimuli

Pharmacokinetics

Absorption: Rapidly absorbed orally (63-73% bioavailability) Distribution: >99% protein bound Volume of distribution: 8-11 L Metabolism: Hepatic via CYP3A4, CYP2C9, and CYP2C8 Excretion: Primarily biliary (86%) with minimal renal excretion (<0.2%) Half-life: 2.7-5.5 hours in adults

Pharmacodynamics

• Reduces early and late-phase bronchoconstriction • Decreases airway hyperresponsiveness • Improves forced expiratory volume (FEV1) within 1 day • Reduces eosinophil count in peripheral blood • Provides 24-hour protection with once-daily dosing

Indications

• Chronic asthma: Prophylaxis and long-term treatment in adults and pediatric patients ≥12 months • Exercise-induced bronchoconstriction: Prevention in patients ≥6 years • Allergic rhinitis: Relief of seasonal (≥2 years) and perennial (≥6 months) allergic rhinitis symptoms • Off-label: Urticaria, adjunct in aspirin-exacerbated respiratory disease (AERD)

Contraindications

Absolute: • Hypersensitivity to montelukast or any component • Phenylketonuria (for chewable tablets containing aspartame) Relative: • History of neuropsychiatric events • Severe hepatic impairment • Concurrent systemic corticosteroid reduction

Dosage & Administration

Chronic asthma (≥15 years): 10 mg once daily in evening Pediatric asthma (6-14 years): 5 mg chewable tablet daily Pediatric asthma (2-5 years): 4 mg chewable tablet or oral granules daily Pediatric asthma (6-23 months): 4 mg oral granules daily Exercise-induced bronchoconstriction (≥6 years): 10 mg at least 2 hours before exercise Allergic rhinitis: Same as asthma dosing by age

Special Populations

Pediatric: Age-specific dosing required Geriatric: No dosage adjustment needed Renal impairment: No dosage adjustment required Hepatic impairment: Caution in severe impairment (Child-Pugh C)

Adverse Effects

Common (>10%): • Headache (18%) • Upper respiratory infection (28%) • Abdominal pain (3-5%) Serious (<1%): • Neuropsychiatric effects (agitation, depression, suicidal ideation) • Eosinophilic conditions • Severe hypersensitivity reactions • Hepatotoxicity

Drug Interactions

• Phenobarbital/Rifampin: Decrease montelukast AUC by 40% • Gemfibrozil: Increases montelukast exposure • CYP2C8 inhibitors: May increase montelukast levels • Systemic corticosteroids: Caution during tapering

Warnings & Precautions

• Black box warning: Serious neuropsychiatric events reported • Monitor for mood changes, suicidal thoughts • Risk of eosinophilic granulomatosis with polyangiitis • Not for acute asthma attacks • Caution in patients with hepatic impairment

Pregnancy & Lactation

Pregnancy: FDA Category B • Limited human data • Use only if potential benefit justifies risk Lactation: Excreted in milk • Consider risk/benefit • Monitor infant for adverse effects

Monitoring Parameters

• Asthma symptom control and FEV1 • Neuropsychiatric symptoms • Liver function tests in hepatic impairment • Eosinophil count if systemic eosinophilia suspected • Growth monitoring in pediatric patients

Patient Counseling

• Take daily even when asymptomatic • Not for acute asthma attacks • Report mood/behavior changes immediately • Chewable tablets contain phenylalanine • Granules can be mixed with soft food • Maintain rescue inhaler availability

Storage & Stability

• Store at 20-25°C (68-77°F) • Protect from moisture and light • Granules stable for 15 minutes in soft foods • Do not freeze

Clinical Pearls

• More effective in aspirin-sensitive asthma • Requires 3-4 days for maximal effect • Consider in asthma patients with allergic rhinitis • Monitor closely during corticosteroid tapering • May reduce nocturnal asthma symptoms • Less effective than inhaled corticosteroids for asthma control

References

• Drugs.com: Montelukast Professional Monograph • FDA Prescribing Information: Singulair (2023) • Global Initiative for Asthma (GINA) Guidelines 2023 • Nayak A, et al. Leukotriene Receptor Antagonists. StatPearls (2023)