What are the treatment options for a dry cough that worsens at rest?

Treatment Options for Dry Cough That Worsens at Rest

Start with honey and lemon as the simplest, cheapest, and often equally effective first-line treatment for dry cough, then escalate to dextromethorphan 60 mg (not the subtherapeutic over-the-counter doses) if symptoms persist or interfere with daily activities. 1, 2

First-Line Non-Pharmacological Approach

• Honey and lemon is recommended as the initial treatment for acute viral dry cough, representing the most cost-effective option with evidence of patient-reported benefit comparable to many pharmacological preparations 3, 1, 2
• Simple voluntary cough suppression through central modulation of the cough reflex may be sufficient to reduce cough frequency, particularly when cough worsens at rest 3, 2

Pharmacological Treatment Algorithm

Primary Antitussive: Dextromethorphan

• Dextromethorphan is the preferred antitussive agent due to its superior safety profile compared to codeine or other opioid alternatives 1, 4, 2
• The effective dose is 60 mg for maximum cough reflex suppression, which can be given as 10-15 mg three to four times daily (maximum 120 mg/day) 1, 4, 2
• Critical pitfall: Most over-the-counter preparations contain subtherapeutic doses (30 mg or less); ensure adequate dosing to achieve clinical benefit 1, 4, 2
• Meta-analysis demonstrates suppression of acute cough with dextromethorphan 4
• This non-sedating opiate is FDA-approved as a cough suppressant 5

For Nocturnal Cough (Worsening at Rest/Night)

• First-generation sedating antihistamines (chlorpheniramine or promethazine) are particularly useful for cough that worsens at rest or disturbs sleep due to their sedative effects 3, 1, 2, 6
• These agents suppress cough but cause drowsiness, making them ideal specifically for nighttime use 3, 1, 2

Adjunctive Short-Term Relief

• Menthol inhalation (menthol crystals BPC or proprietary capsules) suppresses the cough reflex acutely when inhaled, though the effect is short-lived 3, 1, 2
• Useful for quick temporary relief but not sustained suppression 1, 2

Alternative Inhaled Option

• Ipratropium bromide is the only inhaled anticholinergic agent recommended for cough suppression in upper respiratory infections or chronic bronchitis (Level of evidence: fair; benefit: substantial; grade A) 2, 7
• Administered via nebulizer; care must be taken to avoid eye contact with face mask use to prevent pupil enlargement or precipitation of narrow-angle glaucoma 7

What NOT to Use

• Avoid codeine or pholcodine: These opiate antitussives have no greater efficacy than dextromethorphan but carry a significantly worse adverse side effect profile including sedation and addiction potential 3, 1, 4, 2
• Do not suppress productive cough: If the patient is coughing up significant sputum, suppression is contraindicated as cough serves a physiological clearance function 3, 1, 2

When to Escalate or Refer

• If cough persists beyond 3 weeks, discontinue symptomatic treatment and pursue full diagnostic workup for underlying causes (asthma, rhinosinusitis, gastroesophageal reflux, post-viral hypersensitivity) 3, 1, 2, 8
• Red flags requiring immediate evaluation: hemoptysis, breathlessness, prolonged fever, recent hospitalization, or underlying chronic conditions (COPD, heart disease, diabetes, asthma) 3
• For idiopathic chronic cough not responding to standard measures, consider referral to specialist cough clinic for evaluation of heightened cough reflex sensitivity and potential trial of low-dose morphine or other specialized therapies 3, 9

Key Clinical Pearls

• Most acute viral dry cough is self-limiting (1-3 weeks) and often does not require prescribed medication 2, 10
• Cough that worsens at rest suggests airway irritation without excessive secretion formation, typically from viral respiratory infection 10
• The combination of dextromethorphan with sedating antihistamines addresses both the cough reflex and the nocturnal component when cough worsens at rest 6