What are the pharmacological management options for post-viral cough?

Pharmacological Management of Post-Viral Cough

For post-viral cough, inhaled ipratropium bromide should be considered as first-line pharmacological therapy due to its demonstrated efficacy in attenuating cough in controlled trials. 1, 2, 3

Treatment Algorithm

First-Line Therapy

• Inhaled ipratropium bromide is recommended as initial pharmacological treatment for post-viral cough 1, 2, 3
• Simple non-drug measures such as honey should be tried first for mild cases, especially if the cough is not severely distressing 1
• Antibiotics have no role in the treatment of post-infectious cough unless there is confirmed bacterial infection 1, 2

Second-Line Therapy

• Inhaled corticosteroids should be considered when cough adversely affects quality of life and persists despite ipratropium use 1, 2
• Codeine linctus (15 mg/5 mL) or codeine phosphate tablets (15-30 mg every 4 hours as required, up to four doses in 24 hours) can be used if cough is distressing 1
• Dosage of codeine can be increased to a maximum of 30-60 mg four times a day (maximum 240 mg in 24 hours) if necessary 1

Third-Line Therapy

• Morphine sulfate oral solution (10 mg/5 mL) at 2.5-5 mg every 4 hours as required, increasing up to 5-10 mg every 4 hours if needed 1
• For severe paroxysms of post-infectious cough, oral prednisone (30-40 mg daily) for a short, finite period may be prescribed after ruling out other common causes of cough 1, 2
• Central-acting antitussive agents such as dextromethorphan should be considered when other treatments fail 1, 2, 4

Special Considerations

Pertussis (Whooping Cough)

• When cough lasts ≥2 weeks with paroxysms, post-tussive vomiting, or inspiratory whooping sound, consider pertussis infection 1, 2
• Pertussis requires specific diagnosis and treatment with macrolide antibiotics 1, 2

Combination Therapy

• A combination of a β-agonist (salbutamol) and ipratropium bromide has shown efficacy in reducing post-viral cough in clinical trials 5
• This combination can be particularly effective for patients with evidence of bronchial hyperresponsiveness 5

Important Caveats and Pitfalls

• Avoid cough suppressants in patients with chronic bronchitis and bronchiectasis as they can cause sputum retention 1
• Post-infectious cough is self-limited and typically resolves within 3-8 weeks; if cough persists beyond 8 weeks, it should be reclassified as chronic cough and evaluated for other causes 2, 6
• Failure to respond to treatment should prompt consideration of other causes such as upper airway cough syndrome, asthma, or gastroesophageal reflux disease 1, 2
• If a patient is already taking regular morphine, increase the regular dose by a third when treating post-viral cough 1

Monitoring and Follow-up

• Assess response to therapy within 1-2 weeks 7
• Follow up within 4-6 weeks after initial evaluation 2
• If cough persists despite sequential therapies, consider systematic evaluation for other common causes of chronic cough 2, 7