What liquid medication is prescribed for a patient presenting with a cough?

Liquid Medications for Cough

For acute cough, dextromethorphan liquid (30-60 mg) is the recommended first-line pharmacological treatment, though honey and lemon mixtures are equally effective and should be considered first for benign viral cough. 1, 2

First-Line Liquid Options

Non-Pharmacological Approach

• Honey and lemon mixtures should be tried first, as they may be as effective as pharmacological treatments without adverse effects and work through central modulation of the cough reflex 1, 2

Dextromethorphan Liquid (Primary Pharmacological Choice)

• Dextromethorphan liquid is the recommended antitussive due to superior safety profile compared to codeine-based alternatives 1, 2, 3
• Standard over-the-counter dosing (15-30 mg) is often subtherapeutic; optimal dosing is 30-60 mg for effective cough suppression 1, 2
• Maximum cough reflex suppression occurs at 60 mg, with maximum daily dose of 120 mg 1, 2
• Available as extended-release oral suspension providing 12-hour relief 3
• Should be used for short-term symptomatic relief only (typically less than 7 days) 2

Second-Line Liquid Options

For Productive Cough

• Guaifenesin liquid (200-400 mg every 4 hours, up to 6 times daily) is the only recommended expectorant for loosening mucus and making coughs more productive 2, 4, 5
• Guaifenesin inhibits cough reflex sensitivity in patients with upper respiratory infections by potentially increasing sputum volume as a protective barrier 5
• Multiple daily doses needed to maintain 24-hour therapeutic effect with immediate-release liquid formulations 4

For Nocturnal Cough

• First-generation antihistamine liquids (diphenhydramine or chlorpheniramine) can be used specifically for nighttime cough due to sedative properties, but with caution in elderly patients due to anticholinergic effects 1, 2, 6

What NOT to Prescribe

• Codeine-based liquid antitussives should never be prescribed - they have no greater efficacy than dextromethorphan but significantly more adverse effects including drowsiness, nausea, constipation, and physical dependence 1, 2
• Promethazine liquid has no established efficacy for cough suppression and is not recommended 2
• Over-the-counter combination cold medications (except older antihistamine-decongestant combinations) are not recommended until proven effective 7, 8

Critical Safety Considerations

• Check combination liquid products carefully - some contain acetaminophen or other ingredients that can accumulate to toxic levels with higher dextromethorphan doses 1, 2
• Do not suppress productive cough where secretion clearance is beneficial 2
• If cough persists beyond 3 weeks, discontinue antitussive therapy and pursue full diagnostic workup rather than continued symptomatic treatment 1, 2, 8

Special Populations

Elderly Patients

• Dextromethorphan liquid 30-60 mg remains the safest first-line option 2
• No dose adjustment needed for chronic kidney disease as it is hepatically metabolized, not renally excreted 1, 2
• Avoid first-generation antihistamines in patients with cognitive impairment, urinary retention, or fall risk 2

Postinfectious Cough

• Try inhaled ipratropium bromide before central antitussives like dextromethorphan 7, 1, 8
• For severe paroxysms unresponsive to ipratropium and dextromethorphan, consider short-course prednisone 30-40 mg daily 7, 1, 8