Montelukast

Drug Class & Mechanism

Montelukast is an oral leukotriene receptor antagonist (LTRA). It selectively and competitively blocks the cysteinyl leukotriene type 1 (CysLT1) receptor, preventing the binding of leukotrienes (LTC4, LTD4, LTE4). These leukotrienes are potent inflammatory mediators released by mast cells and eosinophils that cause:

Bronchoconstriction
Increased mucus secretion
Airway edema
Eosinophilic inflammation

Indications

Indication	Notes
Asthma (prophylaxis & maintenance)	Particularly useful in children with mild asthma due to concerns about ICS-related growth suppression
Allergic rhinitis (AR)	Seasonal and perennial; less preferred than intranasal corticosteroids or antihistamines
Exercise-induced bronchoconstriction	Effective without the tachyphylactic effects seen with regular LABA use
Aspirin-exacerbated respiratory disease (AERD)	Particularly effective due to significant leukotriene overproduction in this condition

Dosing

Age Group	Dose
Adults & adolescents ≥15 years	10 mg orally once daily (evening)
Children 6–14 years	5 mg chewable tablet once daily
Children 2–5 years	4 mg chewable tablet or granules once daily
Children 6–23 months (asthma)	4 mg oral granules once daily

Clinical Role

As monotherapy: Improves airway function and reduces exacerbations, though not to the same degree as bronchodilators or inhaled corticosteroids (ICS), respectively (Harrison's, p. 7933)
Add-on therapy: Shows modest benefit in patients poorly controlled on high-dose ICS/LABA combinations
Dual disease (asthma + AR): Advantageous when both conditions are present, as it addresses both simultaneously

Safety & Warnings

Neuropsychiatric Effects (Black Box Warning — FDA)

The FDA issued a black box warning for serious neuropsychiatric events, which may include:

Agitation, aggression, anxiety
Depression
Sleep disturbances (nightmares, somnambulism)
Suicidal thoughts or actions

Per CBS Rhinitis guidelines (p. 23): Montelukast should be used for allergic rhinitis only in patients not effectively treated with or unable to tolerate other alternatives.

Due to these safety concerns, montelukast use may decrease over time and is not recommended as first-line for AR when other agents are available.

Pharmacokinetics

Parameter	Value
Bioavailability	~73–64% (food has minimal effect)
Protein binding	>99%
Metabolism	CYP3A4, CYP2C8 (hepatic)
Half-life	~2.7–5.5 hours
Elimination	Primarily biliary/fecal

Key Takeaways

Best suited for mild asthma, aspirin-exacerbated respiratory disease, and patients with co-existing asthma + allergic rhinitis
Not first-line for AR — use only when other therapies (intranasal steroids, antihistamines) fail or are not tolerated
Always counsel patients and caregivers about neuropsychiatric risks before initiating, especially in pediatric patients

This is a shared conversation. Sign in to Orris to start your own chat.