What is the recommended treatment for a patient with a dry and wet cough, considering their age, weight, and potential underlying respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD)?

Management of Dry and Wet Cough

For wet/productive cough in children, prescribe antibiotics targeting common respiratory bacteria (amoxicillin-clavulanate) for 2 weeks, while for dry cough in adults, use dextromethorphan 60 mg (not standard OTC doses) in sugar-free formulations, avoiding cough suppressants entirely when the cough is productive. 1

Critical First Step: Distinguish Wet from Dry Cough

The management approach fundamentally differs based on cough type, and this distinction must be made before any treatment:

Wet/Productive Cough Characteristics

• Loose, self-propagating sound in young children who cannot expectorate 1
• Productive of sputum in older children and adults 1
• Green or yellow sputum suggests bacterial infection requiring medical consultation 2

Dry Cough Characteristics

• Non-productive, irritating, or "tricky" quality 2
• No mucus production 3

Management Algorithm for Children (≤14 years)

For Chronic Wet Cough (>4 weeks duration)

Prescribe 2 weeks of antibiotics targeting Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis based on local sensitivities (typically amoxicillin-clavulanate). 1

• If cough resolves within 2 weeks, diagnose as protracted bacterial bronchitis (PBB) 1
• If wet cough persists after 2 weeks of appropriate antibiotics, extend treatment for an additional 2 weeks 1
• If cough persists after 4 weeks total antibiotic therapy, perform further investigations including flexible bronchoscopy with quantitative cultures and/or chest CT 1

Red Flags Requiring Immediate Investigation (Not Antibiotics)

• Coughing with feeding 1
• Digital clubbing 1
• These require bronchoscopy, CT, aspiration assessment, or immunologic evaluation 1

For Chronic Dry Cough in Children

Do NOT use empirical treatment for upper airway cough syndrome, GERD, or asthma unless specific features of these conditions are present. 1

• Obtain chest radiograph and spirometry (pre- and post-β2 agonist) when age-appropriate 1
• For children >6 years with suspected asthma, consider airway hyperresponsiveness testing 1
• Avoid routine skin prick testing, Mantoux, bronchoscopy, or chest CT unless clinically indicated 1

Management Algorithm for Adults

For Wet/Productive Cough

NEVER suppress productive cough with antitussives, as cough clearance is essential in conditions like pneumonia and bronchiectasis. 1

• Consider guaifenesin (200-400 mg every 4 hours, up to 6 times daily) to help loosen mucus and make coughs more productive 4, 5
• Extended-release guaifenesin formulations provide 12-hourly dosing convenience 5

For Dry/Non-Productive Cough

Prescribe dextromethorphan 60 mg for maximum cough reflex suppression and prolonged relief. 6, 7

Critical Dosing Information

• Standard OTC doses (15-30 mg) are subtherapeutic and should not be prescribed 6, 7
• Maximum cough suppression occurs at 60 mg 6, 7
• Use sugar-free formulations, especially for diabetic patients 7
• Exercise caution with combination products containing paracetamol or other ingredients that may require dose adjustment 6, 7

Alternative Options

• Ipratropium bromide inhaler is effective for post-infectious cough and upper respiratory infections 6, 7
• Low-dose morphine has shown benefit for refractory idiopathic chronic cough 1
• Simple honey and lemon mixtures should be tried before pharmacological treatments 6, 7

Medications to AVOID

Do NOT prescribe codeine or pholcodine—they have no greater efficacy than dextromethorphan but significantly worse adverse effects (drowsiness, nausea, constipation, physical dependence). 1, 6, 7

Special Populations

Diabetic Patients

• Prescribe sugar-free dextromethorphan formulations 7
• Monitor blood glucose more frequently when starting any new cough medication 7
• Avoid combination products with decongestants (pseudoephedrine) that may affect blood pressure 7

Patients with COPD, Asthma, or Underlying Respiratory Disease

• Treat the underlying condition rather than suppressing cough 1
• Cough suppression may be relatively contraindicated when cough clearance is important 1

Duration of Treatment and Mandatory Reassessment

If cough persists beyond 3 weeks, mandatory reassessment is required rather than continuing antitussive therapy. 6, 8

• Post-viral cough typically resolves within 2-3 weeks 6
• Cough lasting >3 weeks requires evaluation for post-viral cough syndrome, pertussis, pneumonia, asthma, or GERD 6, 8
• Chronic cough (>8 weeks) requires full diagnostic workup 7

Critical Pitfalls to Avoid

• NEVER prescribe antibiotics for post-viral dry cough—they have absolutely no role except in suspected pertussis 6, 8
• NEVER suppress wet/productive cough with antitussives 1
• NEVER use standard OTC doses of dextromethorphan (15-30 mg)—they are subtherapeutic 6, 7
• NEVER continue antitussive therapy beyond 3 weeks without reassessing for underlying causes 6, 8
• NEVER use empirical treatment for asthma/GERD in children unless specific features are present 1