What antibiotic is prescribed for a cough lasting 2 months?

Antibiotic Management for 2-Month Cough

A cough lasting 2 months (8 weeks) is classified as chronic cough and antibiotics are NOT indicated unless pertussis is specifically suspected based on paroxysmal episodes. 1

Initial Classification and Approach

A 2-month cough meets the definition of chronic cough (>8 weeks duration), which fundamentally changes the diagnostic and therapeutic approach away from infectious causes toward the common chronic cough triad. 1

When to Consider Antibiotics (Pertussis Only)

Antibiotics should ONLY be prescribed if pertussis is clinically suspected, which requires specific features:

• Paroxysmal cough episodes (sudden, uncontrollable coughing fits) lasting ≥2 weeks 2
• Post-tussive vomiting or inspiratory stridor support but are not required for diagnosis 2
• If pertussis is suspected, start azithromycin immediately without waiting for laboratory confirmation 2

Azithromycin is the preferred first-line antibiotic due to better tolerability and compliance 2

• Alternative: Erythromycin 1-2 g/day for 2 weeks 2
• Alternative: Clarithromycin 2
• Critical caveat: After 2 weeks of symptoms, antibiotics have limited benefit but may still prevent transmission 2
• Isolate patient for 5 days from antibiotic initiation 2

When Antibiotics Are NOT Indicated (Most Cases)

For chronic cough without pertussis features, antibiotics provide no benefit and should be avoided. 3, 4 The evidence is clear:

• Amoxicillin showed no benefit in adults with acute cough, even when pneumonia or bacterial infection was predicted 3
• Antibiotics do not alter the clinical course even when they eliminate bacteria 5
• Inappropriate antibiotic prescribing for cough remains a major problem despite lack of efficacy 4

Systematic Evaluation Algorithm for Chronic Cough

Mandatory Initial Workup

Chest radiography and spirometry are mandatory before proceeding with treatment 1

The Three Common Causes (Address Sequentially)

1. Upper Airway Cough Syndrome (UACS) - First-Line Trial

• Clinical pointers: nasal discharge, throat clearing, postnasal drip sensation, nasal congestion, or rhinorrhea 6
• Treatment: First-generation antihistamine-decongestant combination for 1-2 weeks 6
• If taking an ACE inhibitor, stop it immediately - cough resolves within days to 2 weeks (median 26 days) 6

2. Asthma - Second-Line Trial if UACS Fails

• Clinical pointers: nocturnal worsening, cold air triggers, exercise-induced symptoms 6
• Treatment: Bronchodilators with response expected within 1 week, complete resolution may take up to 8 weeks 6
• Confirm with spirometry and bronchodilator response or bronchoprovocation challenge 6

3. GERD - Third-Line Trial if Both Above Fail

• Treatment: High-dose PPI therapy, dietary modifications, lifestyle changes 6
• Critical timing: Requires patience - response may take 2 weeks to several months, some need 8-12 weeks 6
• Intensive acid suppression with PPIs should be undertaken for a minimum of 2 months 1

Post-Infectious Cough Consideration

If the cough began with an acute respiratory infection 3-8 weeks ago (which would now be at the 2-month mark):

• First-line: Inhaled ipratropium 2, 6
• Second-line: Inhaled corticosteroids if ipratropium fails 6
• For severe paroxysms: Short course of oral prednisone 30-40 mg/day after ruling out other causes 2, 6

Symptomatic Cough Suppression (Non-Antibiotic)

For dry, non-productive cough interfering with quality of life:

• Simple remedies first: Honey and lemon may be as effective as pharmacological treatments 7
• Dextromethorphan 60 mg (not the subtherapeutic OTC doses) for optimal cough reflex suppression 2, 7
• First-generation sedating antihistamines particularly suitable for nocturnal cough 7
• Avoid codeine - no greater efficacy than dextromethorphan but worse side effect profile 2, 7

Common Pitfalls to Avoid

• Do NOT prescribe antibiotics reflexively for chronic cough - they have no role unless pertussis is specifically suspected 3, 4
• Do NOT wait for laboratory confirmation if pertussis is suspected - start macrolide immediately as delay decreases effectiveness 2
• Do NOT use subtherapeutic doses of dextromethorphan - OTC doses are insufficient; 60 mg is needed for optimal effect 2, 7
• Do NOT give up on GERD treatment too early - it may require 8-12 weeks before improvement 6
• Do NOT forget to check for ACE inhibitor use - this is an easily reversible cause 6