What over-the-counter (OTC) medications can be used to treat a persistent cough?

OTC Treatment for Persistent Cough

Start with honey and lemon as first-line treatment, then use dextromethorphan 60 mg (not the standard 30 mg dose) if additional relief is needed, as this provides maximum cough suppression with superior safety compared to codeine-based products. 1

Algorithmic Approach to OTC Cough Treatment

Step 1: First-Line Non-Pharmacological Treatment

• Honey and lemon mixtures are the simplest, cheapest, and often effective initial approach for benign viral cough 1, 2
• Voluntary cough suppression techniques may reduce cough frequency through central modulation of the cough reflex 1
• These simple remedies may be as effective as pharmacological treatments for acute viral cough 2

Step 2: Pharmacological Treatment When Needed

Primary OTC Recommendation: Dextromethorphan

• Dextromethorphan is the preferred antitussive due to superior safety profile compared to opioid alternatives 1, 2
• Critical dosing consideration: Standard OTC dosing (30 mg) is often subtherapeutic 2
• Optimal dose is 60 mg for maximum cough reflex suppression with prolonged effect 1, 2
• Dextromethorphan is a non-sedating opiate that acts centrally to suppress the cough reflex 1
• Caution: Some combination preparations contain additional ingredients like acetaminophen or paracetamol, so check labels carefully when using higher doses 1, 2

Alternative Options for Specific Situations

For nighttime cough disrupting sleep:

• First-generation sedative antihistamines (like chlorpheniramine) can suppress cough and are particularly useful for nocturnal cough due to sedative effects 1, 2
• The drowsiness is actually beneficial when cough interferes with sleep 1

For quick but temporary relief:

• Menthol inhalation suppresses cough reflex acutely but provides short-lived relief 1, 2
• Can be used as menthol crystals or proprietary capsules 1

Step 3: What NOT to Use

Avoid codeine and pholcodine:

• These have no greater efficacy than dextromethorphan but carry significantly worse adverse effect profiles including drowsiness, nausea, constipation, and physical dependence 1, 2
• Not recommended despite their availability 1

Critical Safety Warnings and Contraindications

Do Not Use Dextromethorphan If:

• Currently taking MAOIs (monoamine oxidase inhibitors) or within 2 weeks of stopping MAOI therapy 3
• Cough is productive with excessive phlegm/mucus 3
• Chronic cough associated with smoking, asthma, or emphysema 3
• Patient requires assessment for pneumonia (tachycardia, tachypnea, fever, abnormal chest examination) - pneumonia must be ruled out first 1

Stop Use and Seek Medical Attention If:

• Cough lasts more than 7 days 3
• Cough returns or occurs with fever, rash, or persistent headache 3
• Cough presents with increasing breathlessness (assess for asthma or anaphylaxis) 1
• Significant hemoptysis or possible foreign body inhalation 1
• Cough with fever, malaise, and purulent sputum suggesting serious lung infection 1

Special Allergy Alert:

• Some dextromethorphan products contain sodium metabisulfite, which may cause allergic-type reactions in susceptible individuals 3

Common Pitfalls to Avoid

• Using subtherapeutic doses (30 mg) of dextromethorphan that may not provide adequate relief when 60 mg is the effective dose 2
• Prescribing or recommending codeine-based products which have no efficacy advantage but increased side effects 2
• Not recognizing that approximately 5% of persons of European ethnicity lack normal ability to metabolize dextromethorphan, leading to rapid toxic levels 4
• Failing to check for additional ingredients in combination products when recommending higher doses 1, 2

Duration Expectations

• Most acute viral cough is self-limiting and lasts 1-3 weeks 1
• Reassure patients about typical duration while monitoring for warning signs requiring further evaluation 1