What is the first-line cough suppressant for respiratory congestion?

First-Line Cough Suppressant for Respiratory Congestion

For respiratory congestion with cough, dextromethorphan at 60 mg is the recommended first-line cough suppressant due to its superior safety profile compared to opioid alternatives, though ipratropium bromide should be considered first for upper respiratory infections and bronchitis. 1, 2

Treatment Algorithm by Clinical Context

For Upper Respiratory Infections (URI)

• Ipratropium bromide is the only inhaled anticholinergic agent recommended for cough suppression in URI, with substantial benefit and Grade A recommendation 3, 2
• Simple home remedies like honey and lemon should be tried first, as they may be as effective as pharmacological treatments for benign viral cough 1, 4
• Central cough suppressants (codeine, dextromethorphan) have limited efficacy for URI-related cough and are not recommended for this indication 3

For Acute or Chronic Bronchitis

• Dextromethorphan 60 mg provides maximum cough reflex suppression and is recommended for short-term symptomatic relief (Grade B recommendation) 3, 1, 2
• Peripheral cough suppressants like levodropropizine and moguisteine are recommended with substantial benefit (Grade A recommendation) 3, 2
• Ipratropium bromide is also effective for bronchitis-related cough 3, 2

Critical Dosing Considerations

Standard over-the-counter dosing of dextromethorphan (15-30 mg) is often subtherapeutic; maximum cough reflex suppression occurs at 60 mg 1, 4. This is a common pitfall—the typical OTC dose provides inadequate relief 1, 2.

When prescribing higher doses, exercise caution as some combination preparations contain other ingredients like acetaminophen that could lead to toxicity at higher doses 1

Why Not Codeine?

Codeine is not recommended as first-line therapy despite its historical use 1, 2. The evidence is clear:

• Codeine has no greater efficacy than dextromethorphan 1, 5
• It carries a significantly worse adverse effect profile including drowsiness, nausea, constipation, and risk of physical dependence 1, 2, 4
• The American College of Chest Physicians specifically recommends avoiding codeine due to its poor benefit-to-risk ratio 2

Adjunctive Options for Specific Situations

For Nocturnal Cough

• First-generation sedative antihistamines (like diphenhydramine or promethazine) can suppress cough and are particularly suitable when cough disrupts sleep due to their sedative properties 1, 4

For Quick Temporary Relief

• Menthol by inhalation provides acute but short-lived cough suppression 1, 4

For Postinfectious Cough

• Try inhaled ipratropium before central antitussives 1, 4
• For severe paroxysms, consider prednisone 30-40 mg daily for a short course 1, 4

What NOT to Use

• Albuterol is not recommended for acute or chronic cough not due to asthma 3, 2
• Mucolytics are not recommended for cough suppression in chronic bronchitis 3, 2
• Over-the-counter combination cold medications (except older antihistamine-decongestant combinations) are not recommended until proven effective in randomized controlled trials 3

Common Pitfalls to Avoid

• Using subtherapeutic doses of dextromethorphan (15-30 mg instead of 60 mg) 1, 2, 4
• Prescribing codeine-based antitussives when dextromethorphan is safer and equally effective 1, 2
• Using central cough suppressants for URI-related cough where they have limited efficacy 3, 2
• Applying cough suppressants to productive cough where secretion clearance is beneficial—antitussives should only be used for non-productive cough 1, 4