What are the recommended treatments for managing a dry cough?

Management of Dry Cough

Start with honey and lemon as first-line treatment for acute dry cough, and when pharmacological therapy is needed, use dextromethorphan 60 mg for optimal cough suppression, as it has superior efficacy and safety compared to codeine-based alternatives. 1

First-Line Non-Pharmacological Approach

• Simple home remedies like honey and lemon are the simplest, cheapest, and often as effective as pharmacological treatments for benign viral cough. 1, 2
• Voluntary suppression of cough through central modulation may be sufficient to reduce cough frequency in some patients. 1
• Most acute viral cough is self-limiting, lasting 1-3 weeks, and often does not require prescribed medication. 1

Pharmacological Management When Needed

Dextromethorphan: Preferred Agent

• Dextromethorphan is the recommended first-line antitussive due to its superior safety profile compared to opioid alternatives. 1, 2, 3
• A clear dose-response relationship exists, with maximum cough suppression occurring at 60 mg, which is higher than standard over-the-counter dosing. 1, 2
• Standard OTC dosing (10-15 mg) is often subtherapeutic and may not provide adequate relief. 2
• For optimal effect, prescribe 30-60 mg doses, with a maximum daily dose of 120 mg. 2
• Caution: Check combination preparations carefully, as some contain paracetamol or other ingredients that could lead to overdose at higher dextromethorphan doses. 1, 2

Alternative Pharmacological Options

• First-generation antihistamines with sedative properties (e.g., diphenhydramine, chlorpheniramine) can suppress cough and are particularly useful for nocturnal cough due to their sedative effects. 1, 2
• Menthol inhalation suppresses the cough reflex when inhaled, providing acute but short-lived relief; can be prescribed as menthol crystals or proprietary capsules. 1, 2

Agents NOT Recommended

• Codeine and pholcodine have no greater efficacy than dextromethorphan but carry significant adverse side effect profiles including drowsiness, nausea, constipation, and physical dependence. 1, 2, 4
• Guaifenesin is ineffective for cough suppression. 4

Management Based on Cough Duration

Acute Cough (< 3 weeks)

• Viral upper respiratory tract infections are the predominant cause in primary care settings. 1
• Assess cough characteristics: dry vs. productive, duration, severity, and impact on sleep. 1
• Reassure patients that most acute cough is self-limiting. 1

Postinfectious Cough (3-8 weeks)

• Trial inhaled ipratropium as first-line approach for cough persisting after acute respiratory infection but less than 8 weeks. 1, 2
• Consider inhaled corticosteroids when cough adversely affects quality of life and persists despite ipratropium. 1
• For severe paroxysms, prednisone 30-40 mg daily may be prescribed for a short, finite period after ruling out other common causes. 1, 2
• Central acting antitussives like dextromethorphan should only be considered when other measures fail. 1, 2
• Antibiotics have no role unless bacterial sinusitis or early Bordetella pertussis is suspected. 1

Chronic Cough (> 8 weeks)

• Consider underlying causes requiring specific treatment:
  • GORD (gastroesophageal reflux disease): May require intensive acid suppression with proton pump inhibitors for at least 3 months. 1
  • Upper airway cough syndrome: Trial of topical corticosteroid is recommended. 1
  • Cough-variant asthma/eosinophilic bronchitis: Perform bronchial provocation testing in patients with normal spirometry. 1
• For unexplained chronic cough after workup:
  • Multimodality speech pathology therapy as initial non-pharmacological approach. 1
  • Gabapentin starting at 300 mg once daily, escalating to maximum 1,800 mg daily in two divided doses, with reassessment at 6 months. 1

Clinical Algorithm for Acute Dry Cough

1. Start with honey and lemon mixture for benign viral cough. 1, 2
2. If additional relief needed: Dextromethorphan 30-60 mg (verify no combination ingredients that could cause problems at higher doses). 1, 2
3. For nocturnal cough disrupting sleep: First-generation antihistamine (e.g., diphenhydramine). 1, 2
4. For quick but temporary relief: Menthol inhalation. 1, 2
5. Avoid codeine-containing products due to poor benefit-to-risk ratio. 1, 2, 4

Critical Red Flags Requiring Further Assessment

• Cough with increasing breathlessness: Assess for asthma or anaphylaxis. 1
• Cough with fever, malaise, purulent sputum: May indicate serious lung infection requiring antibiotics. 1
• Significant hemoptysis or possible foreign body inhalation: Requires specialist referral. 1
• Symptoms suggesting pneumonia (tachycardia, tachypnea, fever, abnormal chest examination): Rule out pneumonia before using antitussives. 1

Common Pitfalls to Avoid

• Using subtherapeutic doses of dextromethorphan (less than 60 mg may be inadequate for severe cough). 1, 2, 4
• Prescribing codeine-based antitussives which offer no efficacy advantage but increased side effects. 1, 2, 4
• Failing to consider GORD as a cause for persistent cough, which is a common reason for treatment failure. 1
• Not recognizing that reflux-associated cough may occur without gastrointestinal symptoms. 1
• Continuing antitussive therapy beyond 3 weeks without full diagnostic workup for alternative diagnoses. 2

Special Considerations

• Smoking cessation should be encouraged for smokers as it is accompanied by significant remission in cough symptoms. 1
• Adjust chronic disease medications (asthma, COPD, cardiac failure, diabetes) during acute respiratory infections. 1
• Dry cough affects 16-18% of general populations and is more prevalent in women, possibly due to increased cough reflex sensitivity. 1