Treatment of Dry Cough in Adults
The appropriate drugs for treating dry cough in adults depend critically on the underlying cause: for chronic bronchitis, use codeine or dextromethorphan; for upper respiratory infections (URI), these central suppressants are NOT recommended, but ipratropium bromide may help; and for postinfectious cough, try ipratropium first, then inhaled corticosteroids if needed 1.
Key Principle: Cause-Directed Treatment
The ACCP guidelines emphasize that cough suppressant use must be guided by the specific disorder causing the cough, not just the symptom itself 1. This is crucial because what works for one cause may be ineffective or inappropriate for another.
Treatment by Underlying Cause
For Chronic Bronchitis (Productive or Dry)
Central cough suppressants are recommended:
- Codeine - Grade B recommendation (fair evidence, intermediate benefit) 1
- Dextromethorphan - Grade B recommendation (fair evidence, intermediate benefit) 1
These should be used for short-term symptomatic relief only 1. Codeine has the added benefit of analgesic and sedative effects, which can be particularly helpful if cough is disrupting sleep 2, 3.
Peripheral cough suppressants (where available):
- Levodropropizine or moguisteine - Grade A recommendation (good evidence, substantial benefit) 1
- Meta-analysis shows levodropropizine has superior efficacy compared to central agents like codeine and dextromethorphan, with better tolerability and less somnolence 4, 5
For Upper Respiratory Infections (Common Cold)
Central cough suppressants like codeine and dextromethorphan have limited efficacy and are NOT recommended - Grade D recommendation (good evidence, no benefit) 1, 6.
What IS recommended:
- Ipratropium bromide (inhaled anticholinergic) - Grade A recommendation for URI or bronchitis (fair evidence, substantial benefit) 1
- This is the only inhaled anticholinergic recommended for cough suppression 1
What to avoid:
- Over-the-counter combination cold medications (except older antihistamine-decongestant combinations) - Grade D 6
- Peripheral cough suppressants - Grade D (limited efficacy in URI) 1, 6
For Postinfectious Cough (3-8 weeks after respiratory infection)
Stepwise approach:
First-line: Ipratropium bromide (inhaled) - Grade B recommendation (may attenuate cough) 6
Second-line: Inhaled corticosteroids - Grade E/B recommendation when cough persists despite ipratropium and adversely affects quality of life 6
For severe paroxysms: Oral prednisone 30-40 mg daily for a short, finite period (after ruling out other causes like UACS, asthma, GERD) - Grade C 6
Last resort: Central antitussives (codeine or dextromethorphan) when other measures fail - Grade E/B 6
Important Caveats and Pitfalls
What NOT to Use:
- Albuterol for cough not due to asthma - Grade D (no benefit) 6
- Mucolytics in chronic bronchitis for cough suppression - Grade D (no benefit) 1
- Zinc preparations for common cold cough - Grade D 6
Combination Products:
Recent research shows that bilastine (non-sedating antihistamine) combined with dextromethorphan and phenylephrine is effective for acute dry cough from common cold or allergy, with significantly less drowsiness than traditional sedating antihistamine combinations 7. This represents a newer, non-sedating option when antihistamine properties are desired.
Sedation Considerations:
First-generation antihistamines like chlorpheniramine combined with codeine cause sedation, which can be valuable if cough is disturbing sleep 2. However, newer non-sedating combinations may be preferable for daytime use 7.
Duration of Treatment:
All cough suppressants should be used for short-term symptomatic relief only 1. If cough persists beyond 8 weeks, reconsider the diagnosis rather than continuing empiric suppression 6.
Critical Warning:
Never suppress cough without identifying the underlying cause first. Screen for red flag signs requiring urgent attention, and ensure you're not masking a serious underlying condition 8.