• Leukotriene Receptor Antagonist (CysLT1 blocker)

Parent class:

• Leukotriene Modifiers

Montelukast selectively blocks the CysLT1 receptor.

Leukotrienes (LTC4, LTD4, LTE4) normally cause:

• Bronchoconstriction
• Increased mucus secretion
• Increased vascular permeability
• Eosinophilic airway inflammation

By blocking the receptor:

• ↓ Bronchospasm
• ↓ Airway inflammation
• ↓ Mucus production

Does NOT block leukotriene synthesis — only receptor binding.

• Oral administration
• Once daily dosing
• Hepatic metabolism (CYP3A4, CYP2C9)
• Eliminated via bile

No routine lab monitoring required.

• Asthma (mild persistent or add-on therapy)
• Exercise-induced bronchospasm
• Allergic Rhinitis
• Aspirin-exacerbated respiratory disease (AERD)

Not first-line for moderate or severe asthma.

• 10 mg PO once daily (evening preferred)

Pediatric dosing based on age (chewable formulations available).

Common:

• Headache
• GI upset

Serious:

• Neuropsychiatric effects (boxed warning)
  1. Agitation
  2. Depression
  3. Sleep disturbances
  4. Suicidal ideation (rare)

FDA recommends reserving for patients who cannot tolerate alternative therapy in allergic rhinitis.

• Use caution in patients with history of depression or psychiatric illness
• Not effective for acute asthma attacks

Montelukast:

• Less effective than inhaled corticosteroids
• Useful as add-on therapy
• Helpful in aspirin-sensitive asthma
• Useful in patients with both asthma and allergic rhinitis

See:

• Asthma Management

• Inferior to intranasal corticosteroids
• Consider if antihistamines not tolerated
• Consider if coexisting asthma

See:

• Allergic Rhinitis

• Leukotrienes are potent bronchoconstrictors.
• Useful in aspirin-exacerbated respiratory disease.
• Not a rescue medication.
• Discuss mental health risks before prescribing.
• Often used in pediatric asthma due to oral formulation.

• Leukotriene Modifiers
• Corticosteroids
• Histamine & Antihistamines