Is montelukast (Singulair) more effective than Aerius (desloratadine) for treating a nightly cough?

Montelukast vs Aerius (Desloratadine) for Nightly Cough

For nightly cough, neither montelukast nor Aerius (desloratadine) is the recommended first-line treatment—you should use a first-generation antihistamine like chlorpheniramine or diphenhydramine, ideally combined with a decongestant. 1, 2

Why Second-Generation Antihistamines Like Aerius Don't Work for Cough

• Aerius (desloratadine) and other second-generation antihistamines are ineffective for treating cough because they lack the anticholinergic properties needed to suppress the cough reflex and reduce secretions 1, 2
• Studies specifically showed that newer antihistamines like loratadine, fexofenadine, and terfenadine (in the same class as Aerius) failed to treat cough associated with upper airway problems, in direct contrast to first-generation agents 1, 2
• The mechanism matters: first-generation antihistamines work through their anticholinergic effects, not their antihistamine effects, which is why "non-sedating" alternatives fail 1, 2

Why Montelukast Is Not the Answer Either

• Montelukast is not indicated for non-allergic upper airway cough syndrome and has no proven role in treating isolated nocturnal cough 3
• A 2014 randomized controlled trial definitively showed that montelukast is not effective for postinfectious cough in adults, with no clinically meaningful improvement over placebo 4
• While montelukast does improve nighttime symptoms in seasonal allergic rhinitis 5, this benefit is for rhinitis symptoms, not for isolated cough
• Montelukast is less effective than intranasal corticosteroids for allergic rhinitis and should only be considered as alternative therapy when steroids fail or aren't tolerated 3

The Evidence-Based Approach to Nightly Cough

First-Line Treatment: First-Generation Antihistamines

• Start with chlorpheniramine 4 mg four times daily or diphenhydramine 25-50 mg four times daily 1
• For nocturnal cough specifically, sedating antihistamines are actually advantageous because they suppress cough and help with sleep 6
• Begin with bedtime dosing for several days before advancing to twice-daily dosing to minimize daytime sedation 1, 2

Add a Decongestant for Upper Airway Cough Syndrome

• Combine with pseudoephedrine 120 mg (sustained-release) twice daily if upper airway cough syndrome is suspected 1, 2
• Evidence-based combinations include dexbrompheniramine 6 mg + pseudoephedrine 120 mg twice daily 1, 2
• Improvement typically occurs within days to 2 weeks of starting treatment 1, 2

When to Consider Other Causes

If First-Generation Antihistamines Fail After 2 Weeks:

• Consider gastroesophageal reflux disease (GERD) as an alternative or coexisting cause, which can present as isolated cough without typical reflux symptoms 2
• Evaluate for asthma, though isolated nocturnal cough without wheezing, shortness of breath, or chest tightness is unlikely to be asthma in most cases 6
• Consider postinfectious cough if there was a recent upper respiratory infection, though this typically resolves spontaneously and montelukast won't help 4

Critical Pitfalls to Avoid

• Don't waste time with Aerius or other second-generation antihistamines for cough—they simply don't work for this indication 1, 2
• Don't use montelukast as monotherapy for isolated cough—it's only appropriate when allergic rhinitis is confirmed and intranasal steroids have failed 3
• Avoid first-generation antihistamines in patients with glaucoma, urinary retention, or symptomatic prostatic hypertrophy 1, 2
• Warn patients about sedation and performance impairment, which can occur even without subjective awareness 1

The Bottom Line Algorithm

1. Start with chlorpheniramine 4 mg at bedtime for several days, then advance to four times daily if tolerated 1
2. Add pseudoephedrine 120 mg twice daily if upper airway symptoms are present (postnasal drip, throat clearing, nasal discharge) 1, 2
3. Reassess after 2 weeks—if no improvement, consider GERD or other causes rather than switching to montelukast or Aerius 2
4. Only consider montelukast if confirmed allergic rhinitis is present AND intranasal corticosteroids have failed 3