Montelukast (a cysteinyl leukotriene receptor 1 antagonist) is used as add-on therapy in asthma. Its advantage over inhaled corticosteroids includes:

• A Greater anti-inflammatory efficacy than ICS at all asthma severities
• B Active against the aspirin/NSAID-exacerbated bronchoconstriction pathway, allergic rhinitis, and aspirin-sensitive asthma, with excellent oral bioavailability and no HPA-axis suppression ✓
• C It blocks both LTC4 and LTD4 synthesis at the 5-lipoxygenase level
• D Superior bronchodilation to short-acting beta-2 agonists in acute exacerbations

Explanation

Montelukast selectively antagonises CysLT1 receptors (binding LTC4 and LTD4), reducing bronchospasm, mucus secretion, and airway inflammation. While ICS is more potent for chronic asthma, montelukast has specific advantages: it is orally bioavailable once daily, has no adrenal suppression or local oropharyngeal side effects, is effective in aspirin-exacerbated asthma (by blocking the cysteinyl leukotriene surge), and also improves allergic rhinitis symptoms. It does not inhibit 5-LO synthesis (that is zileuton's mechanism). It is not a bronchodilator for acute use.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.