What is the first‑line prescription antitussive for a generally healthy adult with an acute non‑productive cough?

Best Prescription Cough Medicine for Adults with Acute Non-Productive Cough

Dextromethorphan at 30-60 mg per dose (maximum 120 mg daily) is the first-line prescription antitussive for generally healthy adults with acute non-productive cough, offering superior safety compared to codeine-based alternatives. 1

Recommended First-Line Approach

Non-Pharmacological Options (Try First)

• Simple home remedies like honey and lemon should be considered before prescription medications, as they may be equally effective for benign viral cough and avoid medication side effects. 1, 2
• Voluntary cough suppression through central modulation may reduce cough frequency sufficiently in some patients without any medication. 1, 2

Prescription Pharmacological Treatment

When prescription medication is needed:

• Dextromethorphan is the recommended first-line prescription antitussive due to its superior safety profile compared to opioid alternatives like codeine. 1
• Optimal dosing is 30-60 mg per dose, with maximum cough reflex suppression occurring at 60 mg; this can be prolonged at this dose level. 1, 2
• Standard over-the-counter dosing (10-15 mg) is often subtherapeutic and may not provide adequate relief. 1
• Maximum daily dose should not exceed 120 mg. 1
• For nocturnal cough specifically, a bedtime dose of 15-30 mg may help suppress cough and promote undisturbed sleep. 1

Alternative Prescription Options for Specific Situations

For Nighttime Cough Disrupting Sleep

• First-generation sedating antihistamines (excluding promethazine) can be prescribed when cough primarily disrupts sleep, as their sedative properties help reduce cough while promoting rest. 1, 2
• Promethazine specifically should be avoided due to serious adverse effects including hypotension, respiratory depression, neuroleptic malignant syndrome, and extrapyramidal reactions. 1

For Temporary Quick Relief

• Menthol inhalation (prescribed as menthol crystals or proprietary capsules) provides acute but short-lived cough suppression for temporary symptom relief. 1, 2

Medications to AVOID

Codeine-containing antitussives should NOT be prescribed for the following reasons: 1, 2

• Codeine has no greater efficacy than dextromethorphan for cough suppression. 1, 3
• Codeine carries a significantly higher adverse effect profile including drowsiness, nausea, constipation, and risk of physical dependence. 1, 2
• The British Thoracic Society explicitly recommends against using codeine-containing antitussives for cough management. 1

Critical Safety Considerations

When Prescribing Dextromethorphan

• Exercise caution with higher doses (60 mg) when using combination preparations, as many contain acetaminophen or other ingredients that could reach toxic levels at higher dextromethorphan doses. 1
• Always check the formulation to ensure patients don't exceed safe limits of other ingredients. 1
• Dextromethorphan requires no dose adjustment in patients with chronic kidney disease, as it is metabolized hepatically by CYP2D6 rather than renally excreted. 1

When NOT to Use Antitussives

• Do NOT prescribe dextromethorphan or any cough suppressant for productive cough, as suppressing the protective cough reflex prevents necessary mucus clearance and can worsen outcomes. 4
• Patients requiring assessment for pneumonia (with fever, tachycardia, tachypnea, or abnormal chest examination) should not receive dextromethorphan until pneumonia is ruled out. 2

Common Prescribing Pitfalls to Avoid

1. Prescribing subtherapeutic doses (less than 30 mg) of dextromethorphan that fail to provide adequate cough relief. 1
2. Prescribing codeine-based products despite their lack of efficacy advantage and increased side-effect burden. 1
3. Using cough suppressants for productive cough, which prevents necessary mucus clearance. 4
4. Failing to warn patients about combination products containing acetaminophen when prescribing higher dextromethorphan doses. 1

Red Flags Requiring Immediate Medical Evaluation (Not Just Antitussives)

Patients should seek immediate medical attention if cough is accompanied by: 2

• Hemoptysis (blood in sputum)
• Significant breathlessness or tachypnea
• Fever with purulent sputum and malaise (possible serious lung infection)
• Increasing breathlessness (assess for asthma or anaphylaxis)

Duration of Treatment

• Dextromethorphan should be used for short-term symptomatic relief only. 1
• If cough persists beyond 3 weeks, discontinue antitussive therapy and perform a full diagnostic workup to evaluate for alternative diagnoses. 1