What is the recommended pharmacologic treatment for an otherwise healthy adult with an isolated dry (non‑productive) cough?

Recommended Medicine for Dry Cough in Adults

Direct Recommendation

For an otherwise healthy adult with isolated dry cough, dextromethorphan 60 mg is the preferred pharmacological treatment, offering superior efficacy and safety compared to codeine-based alternatives. 1

However, before reaching for medication, simple home remedies like honey and lemon should be tried first, as they are equally effective for benign viral cough and cost nothing. 1, 2

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Treatment Algorithm

Step 1: First-Line Non-Pharmacological Approach

• Honey and lemon mixture is the simplest, cheapest, and often effective first-line treatment with evidence of patient-reported benefit. 1, 2
• Voluntary cough suppression through central modulation may be sufficient to reduce cough frequency in some patients. 1, 2

Step 2: Pharmacological Treatment When Needed

Preferred Agent: Dextromethorphan

• Dextromethorphan is FDA-approved as a cough suppressant and is the recommended first-line antitussive due to its superior safety profile. 1, 3
• Dosing is critical: Standard over-the-counter doses are often subtherapeutic; maximum cough suppression occurs at 60 mg, with a dose-response relationship clearly demonstrated. 1, 2
• Standard regimen: 10-15 mg three to four times daily (every 6-8 hours), with maximum daily dose of 120 mg. 2
• For nighttime cough: A bedtime dose of 15-30 mg may help suppress cough and promote undisturbed sleep. 2
• Important safety note: Exercise caution with combination preparations containing acetaminophen or other ingredients, as higher doses could lead to excessive amounts of these additional components. 1, 2

Alternative Agent: Benzonatate

• Benzonatate is FDA-approved for symptomatic relief of cough and offers an alternative with a different adverse effect profile, particularly when opioids are contraindicated. 4, 2

For Nocturnal Cough Specifically

• First-generation sedating antihistamines (such as diphenhydramine or chlorpheniramine) can suppress cough and are particularly useful when cough disrupts sleep due to their sedative effects. 1, 2

Short-Term Adjunct: Menthol

• Menthol by inhalation suppresses the cough reflex acutely but provides only short-lived relief; can be prescribed as menthol crystals or proprietary capsules. 1, 2

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Agents NOT Recommended

Codeine and pholcodine should be avoided entirely — they have no greater efficacy than dextromethorphan but carry a significantly worse adverse effect profile including drowsiness, nausea, constipation, and risk of physical dependence. 1, 2, 5

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Critical Pitfalls to Avoid

Common Prescribing Errors

• Using subtherapeutic doses: Most over-the-counter dextromethorphan preparations contain 10-15 mg, which may be inadequate; consider prescribing 30-60 mg for optimal effect. 1, 2
• Suppressing productive cough: Never use cough suppressants for productive cough, as they prevent necessary mucus clearance and can worsen outcomes. 5
• Prescribing codeine-based products: These offer no efficacy advantage but significantly more side effects. 1, 2

When NOT to Use Antitussives

• Do not use dextromethorphan in patients requiring assessment for pneumonia (characterized by tachycardia, tachypnea, fever, or abnormal chest examination findings) — pneumonia must be ruled out first. 1
• Avoid cough suppression in patients with asthma or COPD if cough serves a protective clearance function. 1

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Red Flags Requiring Immediate Medical Evaluation

Patients should seek immediate medical attention if they experience:

• Hemoptysis (coughing up blood) 1
• Significant breathlessness or tachypnea 1
• Fever with purulent sputum and malaise (may indicate serious lung infection) 1
• Cough with increasing breathlessness (assess for asthma or anaphylaxis) 1

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Special Considerations

Duration of Treatment

• Most acute viral cough is self-limiting and lasts 1-3 weeks. 1
• If cough persists beyond 3 weeks, discontinue antitussive therapy and pursue full diagnostic workup for alternative diagnoses rather than continued symptomatic treatment. 2

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

• First-line: Trial inhaled ipratropium before central antitussives. 1, 2
• Second-line: 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

Chronic Cough (>8 Weeks)

• Consider underlying causes such as gastroesophageal reflux disease (GERD), which may require intensive acid suppression with proton pump inhibitors for at least 3 months. 1
• For cough with upper airway symptoms, trial topical corticosteroid. 1
• Perform bronchial provocation testing in patients with normal spirometry without obvious cause. 1

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Evidence Quality Discussion

The British Thoracic Society guidelines strongly support dextromethorphan as the preferred agent based on meta-analysis showing efficacy for acute cough, with a clear dose-response relationship and superior safety profile compared to opioid alternatives. 1 The American College of Chest Physicians concurs, though notes that central cough suppressants have limited efficacy for acute upper respiratory infection cough specifically. 1 This apparent contradiction is resolved by recognizing that dextromethorphan achieves less than 20% cough suppression in acute URI but 40-60% reduction in chronic bronchitis/COPD-related cough. 1 For otherwise healthy adults with isolated dry cough, the recommendation for dextromethorphan at appropriate doses (60 mg for maximum effect) remains sound, with honey and lemon as an equally valid first-line option. 1, 2