What are the recommendations for using cough syrup to treat a cough?

Cough Syrup Recommendations

For acute cough from the common cold, over-the-counter cough syrups containing dextromethorphan are the most effective antitussive option, while most combination cough preparations should be avoided unless they contain first-generation antihistamine/decongestant ingredients. 1

Acute Cough from Common Cold

First-Line Recommendations

• Dextromethorphan-containing cough syrups are the preferred antitussive with superior efficacy and better side effect profile compared to codeine and other opioids 2
• Maximum cough suppression occurs at 60 mg doses (higher than typical over-the-counter preparations), with evidence showing 21-25% reduction in cough frequency 2, 3
• Home remedies such as honey and lemon should be recommended first before prescription medications 1

What NOT to Use

• Over-the-counter combination cold medications should NOT be used unless they contain older antihistamine/decongestant ingredients, as newer nonsedating antihistamines are ineffective for cough 1
• Combination cough preparations should generally not be prescribed 4
• Antibiotics are not indicated for acute cough from common cold and should be avoided 1

Alternative Options

• First-generation antihistamines combined with decongestants are strongly recommended for acute cough from common cold (unless contraindications exist such as glaucoma, benign prostatic hypertrophy, hypertension, renal failure, GI bleeding, or heart failure) 1
• Naproxen (NSAID) is also strongly recommended as an alternative 1
• Menthol lozenges or vapor provide acute, short-lived cough suppression and can be used as adjunct therapy 1, 2

Guaifenesin (Expectorant)

• Guaifenesin helps loosen phlegm and thin bronchial secretions to make coughs more productive 5
• Should NOT be used if cough occurs with too much phlegm already, or if cough is chronic (as with smoking, asthma, chronic bronchitis, or emphysema) 5
• Stop use if cough lasts more than 7 days, comes back, or is accompanied by fever, rash, or persistent headache 5

Chronic Cough (>3 weeks)

Key Principle

• Treat the underlying cause rather than suppressing the cough symptomatically 1
• Cough suppression may be relatively contraindicated when cough clearance is important 1

Common Underlying Causes to Address

• GERD: Intensive acid suppression with proton pump inhibitors and alginates for minimum 3 months 1
• Upper airway disease/rhinosinusitis: Trial of topical corticosteroid in presence of prominent upper airway symptoms 1
• Asthma/eosinophilic airway inflammation: Two-week oral steroid trial; if no response, eosinophilic inflammation is unlikely 1
• ACE inhibitor-induced cough: No patient with troublesome cough should continue ACE inhibitors 1
• Smoking: Smoking cessation should be strongly encouraged as it leads to significant remission in cough symptoms 1, 6

When Symptomatic Treatment is Appropriate

• Only when the cause remains unknown or when cough performs no useful function and complications represent a potential hazard 4
• For refractory chronic cough not responding to treatment of underlying causes, consider opioids (particularly in palliative settings) or gabapentin 2

Red Flags Requiring Medical Evaluation

Seek medical attention immediately if: 1, 6, 2

• Coughing up blood
• Breathlessness
• Prolonged fever and feeling unwell
• Pre-existing medical conditions (COPD, heart disease, diabetes, asthma)
• Recent hospitalization
• Symptoms persist for more than 3 weeks

Important Caveats

• Most short-term coughs are viral and self-limiting; patients often don't need to see a doctor 1
• The common cold should be ruled out before diagnosing acute bronchitis, as bronchitis diagnosis leads to inappropriate antibiotic prescribing in 65-80% of cases 1
• Adequate hydration should be encouraged in all patients with cough 2