What liquid cough medication can help alleviate a cough in adults and children over 12 years old?

Liquid Cough Medications for Adults and Children Over 12

For adults and children over 12 years old with dry cough, order dextromethorphan liquid (syrup) at a dose of 10-20 mL (containing 10-30 mg) every 4-12 hours, with a maximum of 120 mg daily, as this is the preferred antitussive due to superior safety compared to codeine-based alternatives. 1, 2, 3

Specific Liquid Formulations to Order

First-Line: Dextromethorphan Liquid

• Dextromethorphan syrup/liquid is the recommended first-line pharmacological option for cough suppression in adults and children over 12 years 1, 2
• Dosing for adults and children ≥12 years: 10 mL every 12 hours (extended-release formulation), not to exceed 20 mL in 24 hours 3
• Alternative immediate-release dosing: 10-15 mg (approximately 5-7.5 mL of standard concentration) three to four times daily, with maximum daily dose of 120 mg 4, 2
• For maximum cough suppression: A single 60 mg dose can be used for severe cough, though this is higher than standard over-the-counter dosing 1, 2
• Dextromethorphan has equivalent efficacy to codeine but significantly fewer adverse effects (no drowsiness, nausea, constipation, or physical dependence) 1, 2

Important Prescribing Considerations

• Standard over-the-counter doses are often subtherapeutic - maximum cough reflex suppression occurs at 60 mg with a clear dose-response relationship 1, 2
• Check combination products carefully - some dextromethorphan preparations contain acetaminophen or other ingredients that could lead to overdose at higher doses 4, 2
• Dextromethorphan is a non-sedating opiate that acts centrally to suppress the cough reflex 1

Alternative Liquid Options

Guaifenesin Liquid (For Productive Cough)

• Dosing for adults and children ≥12 years: 10-20 mL (2-4 teaspoonfuls) every 4 hours, not to exceed 6 doses in 24 hours 5
• Note: Guaifenesin is an expectorant, not a cough suppressant - it helps loosen mucus rather than suppress cough 5
• This is NOT appropriate for dry cough - only use if cough is productive with mucus 5

Simple Linctus (Demulcent)

• Dosing: 5 mL three to four times daily 4
• Acts as a soothing agent rather than pharmacological suppressant 4

Codeine-Containing Liquids (NOT RECOMMENDED)

• Codeine and pholcodine should be avoided - they have no greater efficacy than dextromethorphan but significantly more adverse effects including drowsiness, nausea, constipation, and physical dependence 1, 2
• Codeine dosing if absolutely necessary: 30-60 mg four times daily 4

Non-Pharmacological First-Line Approach

Before Ordering Medication

• Honey and lemon mixture is the simplest, cheapest first-line treatment with evidence of patient-reported benefit 1, 2
• This should be tried first for benign viral cough before pharmacological options 1, 6
• Voluntary cough suppression through central modulation may be sufficient to reduce cough frequency 1, 2

Clinical Algorithm for Liquid Cough Medication Selection

1. Start with non-pharmacological: Recommend honey and lemon mixture first 1, 2

2. If pharmacological treatment needed for dry cough:

   • Order dextromethorphan liquid 10-15 mg (5-7.5 mL) three to four times daily 1, 2
   • Can increase to 60 mg single dose for severe symptoms if needed 1, 2

3. For nocturnal cough disrupting sleep:

   • Consider first-generation antihistamine liquid (e.g., diphenhydramine) due to sedative properties 1, 2
   • These suppress cough but cause drowsiness, making them suitable specifically for nighttime use 1, 2

4. For productive cough with mucus:

   • Order guaifenesin liquid 10-20 mL every 4 hours 5

Critical Pitfalls to Avoid

• Do NOT prescribe codeine-containing liquids - they offer no advantage over dextromethorphan but have substantially worse side effect profiles 1, 2
• Do NOT use subtherapeutic doses - standard OTC dosing of dextromethorphan is often inadequate; consider 30-60 mg doses for effective suppression 1, 2
• Do NOT suppress productive cough in conditions like pneumonia or bronchiectasis where clearance is essential 1
• Check for combination products to avoid accidental overdose of acetaminophen or other ingredients when using higher dextromethorphan doses 4, 2

When to Avoid Cough Suppressants

• Cough with increasing breathlessness - assess for asthma or anaphylaxis 1
• Cough with fever, malaise, purulent sputum - may indicate serious lung infection requiring antibiotics, not suppressants 1
• Significant hemoptysis or possible foreign body - requires specialist referral 1
• Patients with COPD or asthma - treat underlying disease first rather than suppressing protective cough 2

Duration of Treatment

• Use dextromethorphan for short-term symptomatic relief only 2
• If cough persists beyond 3 weeks, discontinue antitussive therapy and perform full diagnostic workup 2
• Persistent cough requires evaluation for underlying causes (GERD, post-nasal drip, asthma) rather than continued suppression 1