What is the recommended treatment for a dry cough?

Treatment of Dry Cough

Start with honey and lemon as first-line treatment, then use dextromethorphan 30-60 mg (not the subtherapeutic over-the-counter doses) if pharmacological therapy is needed. 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 acute viral dry cough. 1, 2
• Voluntary suppression of cough may be sufficient to reduce cough frequency through central modulation of the cough reflex. 1
• Most acute viral cough is benign, self-limiting, and lasts 1-3 weeks, often not requiring prescribed medication. 1

First-Line Pharmacological Treatment: Dextromethorphan

When home remedies are insufficient, dextromethorphan is the preferred antitussive:

• Dextromethorphan is recommended as the preferred pharmacological option due to superior efficacy and better safety profile compared to codeine and other opioid antitussives. 1, 3, 4
• Dextromethorphan is a non-sedating opiate that effectively suppresses the cough reflex centrally. 1
• A dose-response relationship exists with maximum cough suppression occurring at 60 mg, which is higher than standard over-the-counter preparations. 1, 2
• Standard over-the-counter dosing is often subtherapeutic and may not provide adequate relief. 1, 2
• Recommended dosing is 10-15 mg three to four times daily, with maximum daily dose of 120 mg. 2
• For severe cough requiring maximum suppression, a single 60 mg dose can be used. 2
• Exercise caution with combination preparations as some contain additional ingredients like paracetamol/acetaminophen that could lead to overdose at higher dextromethorphan doses. 1, 2

Alternative Pharmacological Options

For Nocturnal Cough

• First-generation antihistamines with sedative properties (e.g., diphenhydramine) can suppress cough and are particularly useful when cough disrupts sleep. 1, 2, 3
• The sedative effect is valuable specifically for nighttime cough management. 1

For Short-Term Relief

• Menthol suppresses cough reflex when inhaled and provides acute but short-lived relief. 1, 2
• Menthol can be prescribed as menthol crystals or proprietary capsules. 1

For Postinfectious Cough (Persisting After Acute Infection but <8 Weeks)

• Trial inhaled ipratropium as first-line approach before central antitussives. 1, 2
• Inhaled corticosteroids may be considered when cough adversely affects quality of life and persists despite ipratropium. 1
• For severe paroxysms, prednisone 30-40 mg daily 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

What NOT to Use

• Codeine and pholcodine have no greater efficacy than dextromethorphan but have significant adverse side effect profiles including drowsiness, nausea, constipation, and physical dependence. 1, 2, 3
• Codeine is specifically not recommended despite being the most researched drug in this field. 1

Clinical Algorithm for Dry Cough Management

1. Start with honey and lemon mixture for benign viral cough 1, 2
2. Add voluntary cough suppression techniques 1
3. If additional relief needed, prescribe dextromethorphan 30-60 mg (verify no contraindicated ingredients in combination products) 1, 2, 3
4. For nighttime cough disrupting sleep, add first-generation antihistamine 1, 2, 3
5. For quick but temporary relief, consider menthol inhalation 1, 2
6. For postinfectious cough, try inhaled ipratropium before dextromethorphan 1, 2

Critical Pitfalls to Avoid

• Using subtherapeutic doses of dextromethorphan (standard OTC doses) that may not provide adequate relief. 1, 2
• Prescribing codeine-based antitussives which have no efficacy advantage but increased side effects. 1, 3
• Failing to check combination products for additional ingredients like acetaminophen when prescribing higher dextromethorphan doses. 1, 2
• If cough persists beyond 3 weeks, perform full diagnostic workup rather than continuing antitussive therapy alone. 2

Red Flags Requiring Further Assessment

• Cough with increasing breathlessness (assess for asthma or anaphylaxis). 1
• Cough with fever, malaise, or purulent sputum (may indicate serious lung infection). 1
• Significant hemoptysis or possible foreign body inhalation (requires specialist referral). 1
• Cough persisting beyond 8 weeks (consider diagnoses other than postinfectious cough). 1