What is the best over-the-counter (OTC) medication for a dry, persistent cough?

Best Over-the-Counter Product for Dry Persistent Cough

For a dry, persistent cough, dextromethorphan at 30-60 mg is the recommended over-the-counter antitussive, with honey and lemon as an equally effective first-line alternative. 1

First-Line Approach

Start with simple home remedies before pharmacological treatment:

• Honey and lemon mixtures are the simplest, cheapest, and often as effective as medications for dry cough 1, 2
• These work through central modulation of the cough reflex and provide a demulcent coating effect 1, 2
• Voluntary cough suppression techniques may be sufficient to reduce cough frequency in some patients 1, 2

Recommended Pharmacological Option: Dextromethorphan

If home remedies are insufficient, dextromethorphan is the preferred OTC antitussive:

• Dextromethorphan is a non-sedating opiate that effectively suppresses the cough reflex centrally 1, 3
• The optimal dose is 30-60 mg for maximum cough suppression, which is higher than standard OTC dosing 1, 2
• Standard OTC doses (10-15 mg) are often subtherapeutic 1, 2
• Maximum daily dose should not exceed 120 mg 1
• A dose-response relationship exists, with maximum suppression at 60 mg 1

Important Safety Considerations

• Check combination products carefully - many dextromethorphan preparations contain additional ingredients like acetaminophen or paracetamol that could lead to overdose at higher doses 1, 2
• Use caution with extended-release formulations 3
• Dextromethorphan should only be used for short-term symptomatic relief 1, 2

Alternative OTC Options

For nocturnal cough disrupting sleep:

• First-generation antihistamines with sedative properties (like diphenhydramine or chlorpheniramine) can suppress cough and are particularly useful for nighttime symptoms 1, 2
• The sedative effect is beneficial when cough interferes with sleep 1

For quick but temporary relief:

• Menthol inhalation (crystals or proprietary capsules) suppresses the cough reflex acutely but provides only short-lived relief 1, 2

What NOT to Use

Avoid codeine-containing products:

• Codeine has no greater efficacy than dextromethorphan but has significantly more adverse effects including drowsiness, nausea, constipation, and physical dependence 1, 2
• The British Thoracic Society specifically recommends against codeine due to poor benefit-to-risk ratio 1

Other ineffective options:

• Over-the-counter combination cold medications (except older antihistamine-decongestant combinations) are not recommended until proven effective 4
• Central cough suppressants have limited efficacy for acute cough due to upper respiratory infection 4

When to Seek Further Evaluation

Stop self-treatment and seek medical attention if:

• Cough persists beyond 3 weeks - requires full diagnostic workup rather than continued antitussive therapy 1, 2
• Cough accompanied by increasing breathlessness (assess for asthma or anaphylaxis) 1
• Fever, malaise, or purulent sputum present (may indicate serious lung infection) 1
• Significant hemoptysis or possible foreign body inhalation 1

Practical Treatment Algorithm

1. Start with honey and lemon for 1-2 weeks 1, 2
2. Add dextromethorphan 30-60 mg if inadequate relief (check for combination products) 1, 2
3. Consider first-generation antihistamine if cough disrupts sleep 1, 2
4. Use menthol inhalation for quick temporary relief as needed 1, 2
5. Seek medical evaluation if no improvement after 3 weeks or red flags develop 1, 2

Common Pitfalls to Avoid

• Using subtherapeutic doses of dextromethorphan (10-15 mg) that provide inadequate relief 1, 2
• Choosing codeine-based products which have no efficacy advantage but increased side effects 1, 2
• Inadvertently overdosing on acetaminophen or other ingredients in combination dextromethorphan products 1, 2
• Continuing antitussive therapy beyond 3 weeks without medical evaluation 1, 2