How should a dry (non‑productive) cough be treated, including home care measures, over‑the‑counter antitussives, and red‑flag signs that require medical evaluation?

Management of Dry (Non-Productive) Cough

Start with honey and lemon as first-line treatment, then escalate to dextromethorphan 30-60 mg (not the subtherapeutic 10-15 mg found in most OTC products) if symptoms persist, and avoid codeine-based products entirely due to their poor benefit-to-risk ratio. 1, 2

First-Line Home Remedies

Simple home measures should always be tried first before pharmacological intervention:

• Honey and lemon mixture is the simplest, cheapest, and often most effective first-line treatment with evidence of patient-reported benefit 1, 2
• These remedies work through central modulation of the cough reflex and provide a demulcent coating effect on irritated airways 1, 2
• Voluntary cough suppression techniques may be sufficient to reduce cough frequency through central modulation alone 1, 3

Pharmacological Treatment: Dextromethorphan

When home remedies fail, dextromethorphan is the preferred antitussive agent:

Optimal Dosing Strategy

• The therapeutic dose is 30-60 mg, NOT the standard OTC dose of 10-15 mg which is subtherapeutic 1, 2
• Maximum cough suppression occurs at 60 mg and can be prolonged 1, 3
• Standard dosing regimen: 10-15 mg three to four times daily, with maximum daily dose of 120 mg 1
• A bedtime dose of 15-30 mg may help suppress nighttime cough and promote sleep 1

Critical Safety Considerations

• Check combination products carefully—many contain acetaminophen or other ingredients that could reach toxic levels at higher dextromethorphan doses 1, 3
• Dextromethorphan has superior safety compared to codeine: no physical dependence, less sedation, no constipation 1

Efficacy Profile

• Reduces cough frequency by approximately 40-60% in chronic bronchitis/COPD-related cough 1
• Less effective (<20% suppression) for acute upper respiratory infection cough 1
• Meta-analysis demonstrates effectiveness for acute cough with dose-response relationship 1

Alternative OTC Options

For specific clinical scenarios:

• First-generation sedating antihistamines (diphenhydramine, chlorpheniramine) are particularly useful for nocturnal cough due to sedative effects 1, 2, 4
• Menthol inhalation (crystals or proprietary capsules) provides acute but short-lived cough suppression when inhaled 1, 2
• Benzonatate is FDA-approved for symptomatic cough relief and offers an alternative mechanism of action 5

What NOT to Use

Avoid these agents due to poor efficacy-to-risk ratios:

• Codeine and pholcodine have no greater efficacy than dextromethorphan but significantly more adverse effects (drowsiness, nausea, constipation, physical dependence) 1, 2
• Over-the-counter combination cold medications lack proven effectiveness 2
• Promethazine has no established efficacy for cough suppression 1

Red-Flag Signs Requiring Immediate Medical Evaluation

Stop self-treatment and seek medical attention if any of the following occur:

• Hemoptysis (any amount of blood in sputum) 1
• Increasing breathlessness or tachypnea suggesting asthma, anaphylaxis, or pneumonia 1, 2
• Fever, malaise, or purulent sputum indicating possible serious lung infection 1, 2
• Tachycardia or abnormal chest examination findings suggesting pneumonia 1
• Cough persisting beyond 3 weeks requires full diagnostic workup rather than continued antitussive therapy 1, 2
• Suspected foreign body inhalation requires specialist referral 1

Common Pitfalls to Avoid

Critical errors that lead to treatment failure:

• Using subtherapeutic doses of dextromethorphan (10-15 mg) when 30-60 mg is needed for adequate suppression 1, 2
• Prescribing codeine-based products despite no efficacy advantage and increased side effects 1, 2
• Suppressing productive cough in conditions like pneumonia or bronchiectasis where clearance is essential 1
• Failing to consider underlying causes (GERD, asthma, post-nasal drip) in persistent cough beyond 3 weeks 6, 7
• Not recognizing that reflux-associated cough may occur without gastrointestinal symptoms 1

Algorithmic Approach to Dry Cough Management

Follow this stepwise escalation:

1. Week 1: Honey and lemon mixture plus voluntary cough suppression techniques 1, 2
2. If inadequate relief: Add dextromethorphan 30-60 mg (check for combination products) 1, 2
3. For nighttime symptoms: Consider first-generation antihistamine at bedtime 1, 2
4. For quick temporary relief: Menthol inhalation as needed 1, 2
5. If cough persists >3 weeks: Stop antitussives and pursue diagnostic workup for underlying causes 1, 2

Special Populations

• Chronic kidney disease: No dose adjustment needed for dextromethorphan as it is hepatically metabolized via CYP2D6, not renally excreted 1
• Children: Cough medicines lack efficacy in pediatric populations and can cause complications; avoid in young children 8
• Smokers: Encourage smoking cessation as it leads to significant remission in cough symptoms 1