What is the best symptomatic treatment for cough in adults?

Best Symptomatic Treatment for Cough in Adults

For acute dry cough in adults, start with simple home remedies like honey and lemon as first-line treatment, then escalate to dextromethorphan 30-60 mg (not the subtherapeutic over-the-counter doses) if pharmacological intervention is needed, avoiding codeine-based products entirely due to their equivalent efficacy but significantly worse side effect profile. 1, 2

First-Line Non-Pharmacological Approach

• Simple home remedies such as honey and lemon are the simplest, cheapest, and often as effective as pharmacological treatments for benign viral cough 1, 2
• Voluntary suppression of cough through central modulation may be sufficient to reduce cough frequency in some patients 1, 2
• These approaches work through central modulation of the cough reflex without the adverse effects of pharmacological agents 2

Pharmacological Treatment Algorithm

When to Escalate to Medications

• If non-pharmacological measures fail to provide adequate relief 1
• When cough significantly interferes with daily activities or sleep 3
• For severe paroxysms requiring immediate symptom control 2

Preferred Pharmacological Agent: Dextromethorphan

Dextromethorphan is the recommended first-line antitussive due to its superior safety profile compared to opioid alternatives 1, 2

Critical dosing consideration: Standard over-the-counter dosing is often subtherapeutic 1, 2

• Effective dose: 30-60 mg for optimal cough suppression 1, 2
• Maximum cough reflex suppression occurs at 60 mg 1, 2
• Standard dosing: 10-15 mg three to four times daily, with maximum daily dose of 120 mg 2
• A dose-response relationship exists, with higher doses providing better suppression 1

Important safety warning: Exercise caution with combination preparations containing acetaminophen or other ingredients when using higher doses 2

Alternative Options for Specific Situations

For nocturnal cough disrupting sleep:

• First-generation sedating antihistamines can suppress cough through their sedative properties 1, 2
• Particularly useful when cough is preventing sleep 1
• Note: These cause drowsiness, which is the intended effect for nighttime use 1, 2

For quick but temporary relief:

• Menthol by inhalation suppresses cough reflex acutely but effect is short-lived 1, 2
• Can be prescribed as menthol crystals or proprietary capsules 1

What NOT to Use

Codeine and pholcodine should be avoided entirely 1, 2

• These have no greater efficacy than dextromethorphan 1, 2
• They carry a significantly worse adverse effect profile including drowsiness, nausea, constipation, and physical dependence 1, 2
• Despite being the most researched drug in this field, codeine is less preferred due to greater side effects 3

Other agents with limited or no evidence:

• Guaifenesin (expectorant) is indicated only for productive cough to help loosen mucus, not for dry cough suppression 4
• Antihistamines alone (without sedative properties) are ineffective for cough 3
• Newer non-sedating antihistamines are ineffective against cough 5

Special Considerations and Red Flags

When to avoid antitussives and seek further evaluation:

• Cough with increasing breathlessness (assess for asthma or anaphylaxis) 1
• Cough with fever, malaise, or purulent sputum (may indicate serious lung infection requiring antibiotics, not suppression) 1
• Significant hemoptysis or possible foreign body inhalation (requires specialist referral) 1
• Cough lasting more than 3 weeks requires full diagnostic workup rather than continued antitussive therapy 2
• Patients requiring assessment for pneumonia (tachycardia, tachypnea, fever, abnormal chest examination) should not receive dextromethorphan until pneumonia is ruled out 1

Common Pitfalls to Avoid

• Using subtherapeutic doses of dextromethorphan (standard OTC doses) that provide inadequate relief 1, 2
• Prescribing codeine-based antitussives which have no efficacy advantage but increased side effects 1, 2
• Suppressing productive cough where clearance of secretions is beneficial 2
• Failing to consider underlying causes such as GERD, which may require intensive acid suppression with proton pump inhibitors for at least 3 months 1
• Not recognizing that reflux-associated cough may occur without gastrointestinal symptoms 1

Treatment Duration

• Dextromethorphan should be used for short-term symptomatic relief only 2
• Discontinue if cough persists beyond 3 weeks and pursue diagnostic evaluation 2
• Most acute viral cough is self-limiting and lasts 1-3 weeks 1

For Refractory Cases

• Consider inhaled ipratropium before escalating to stronger central antitussives 2
• For severe paroxysms of postinfectious cough, short-course prednisone 30-40 mg daily may be indicated 2
• For opioid-resistant cough, peripherally-acting antitussives like levodropropizine may be considered 2
• Nebulized lidocaine may be considered as a last resort for refractory cases 2