What is the appropriate treatment for cough?

Treatment of Cough

Begin with a systematic approach based on cough duration: treat acute cough (<3 weeks) with first-generation antihistamine/decongestant combinations, and manage chronic cough (>8 weeks) by sequentially targeting the three most common causes—upper airway cough syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD). 1, 2, 3

Initial Assessment and Red Flags

• Determine cough duration to guide your treatment strategy: acute (<3 weeks), subacute (3-8 weeks), or chronic (>8 weeks). 1, 2, 3

• Obtain a chest radiograph to exclude pneumonia, pulmonary embolism, lung cancer, interstitial disease, heart failure, or structural abnormalities. 1, 2, 3

• Review all medications immediately and discontinue ACE inhibitors if present, as they cause persistent dry cough in up to 16% of patients, with median resolution time of 26 days after cessation. 3, 4

• Advise immediate smoking cessation for all smokers, as this alone can resolve cough within 4 weeks. 3

Treatment Algorithm for Acute Cough (<3 Weeks)

For acute cough due to common cold or viral upper respiratory infection, prescribe a first-generation antihistamine plus decongestant combination as first-line therapy. 5, 2

• Do not prescribe antibiotics for acute bronchitis or common cold, as they provide no benefit and cough typically lasts 10-20 days regardless of treatment. 4

• For symptomatic relief when cough interferes with sleep or daily activities:

  • Dextromethorphan 60 mg (not standard OTC doses of 15-30 mg, which are subtherapeutic) provides maximum cough reflex suppression with prolonged effect. 2, 4
  • Honey and lemon mixtures are effective home remedies that should be tried before pharmacologic agents. 3, 4
  • First-generation sedating antihistamines (e.g., chlorpheniramine) are particularly suitable for nocturnal cough due to their sedative properties. 2, 6

• Stop dextromethorphan and reassess if cough persists beyond 7 days or returns with fever, rash, or headache, as these may indicate serious conditions. 7

• If cough persists beyond 3 weeks, discontinue symptomatic treatment and evaluate for post-viral cough, pertussis, pneumonia, or transition to chronic cough workup. 4

Treatment Algorithm for Subacute Cough (3-8 Weeks)

For postinfectious cough following acute respiratory infection, trial inhaled ipratropium bromide as first-line therapy. 1

• If ipratropium fails and cough adversely affects quality of life, add inhaled corticosteroids. 1

• Rule out pertussis in patients with paroxysmal cough, especially with epidemiologic linkage to confirmed cases. 1

  • If pertussis is confirmed or probable, prescribe a macrolide antibiotic (erythromycin, azithromycin, or clarithromycin) and isolate patient for 5 days from treatment start. 1
  • Do not use long-acting β-agonists, antihistamines, corticosteroids, or pertussis immunoglobulin for whooping cough, as there is no evidence of benefit. 1

• If cough persists beyond 8 weeks, transition to chronic cough evaluation. 1

Treatment Algorithm for Chronic Cough (>8 Weeks)

Sequentially evaluate and treat the three most common causes in order: UACS first, then asthma, then GERD, using additive therapy as multiple causes are present in 59% of cases. 1, 2, 3

Step 1: Treat Upper Airway Cough Syndrome (UACS)

• Initiate first-generation antihistamine/decongestant combination (e.g., chlorpheniramine plus pseudoephedrine) as empiric first-line therapy. 1, 2, 3

• Allow 2-4 weeks for adequate therapeutic trial before concluding treatment failure. 1

Step 2: Treat Asthma or Nonasthmatic Eosinophilic Bronchitis

• If UACS treatment fails or cough persists, initiate inhaled corticosteroids combined with long-acting β-agonists for suspected asthma. 3

• For nonasthmatic eosinophilic bronchitis, use inhaled corticosteroids alone as first-line treatment. 3

• Allow adequate treatment duration (typically 6-8 weeks) before declaring treatment failure. 1

Step 3: Treat Gastroesophageal Reflux Disease (GERD)

• If cough persists after addressing UACS and asthma, initiate high-dose proton pump inhibitor (PPI) therapy twice daily along with dietary modifications (avoid late meals, elevate head of bed, eliminate trigger foods). 1, 2, 3

• Add prokinetic agent (metoclopramide) if little or no response to PPI therapy after 8-12 weeks. 1

• Consider 24-hour esophageal pH monitoring or upper endoscopy if empiric GERD treatment fails. 1

Step 4: Advanced Evaluation if All Treatments Fail

• Obtain high-resolution CT scan to evaluate for bronchiectasis, interstitial lung disease, or occult airway disease. 1

• Perform bronchoscopy to look for endobronchial tumor, sarcoidosis, suppurative infection, eosinophilic bronchitis, or lymphocytic bronchitis. 1

• Evaluate for aspiration and swallowing disorders by questioning about cough while eating/drinking and referring to speech-language pathologist if positive. 1

• Consider referral to cough specialist before labeling as unexplained/idiopathic cough. 1, 3

Symptomatic Cough Suppressants for Refractory Cases

Reserve symptomatic suppressants for when specific therapy fails, cause is unknown, or cough serves no useful function (e.g., lung cancer). 1, 8

• Dextromethorphan 60 mg provides maximum suppression with acceptable side effect profile. 2, 4

• Benzonatate 100-200 mg three to four times daily works peripherally by anesthetizing stretch receptors and has no systemic effects. 4

• Low-dose morphine (slow-release preparation) may be considered for severe refractory chronic cough or terminal cancer patients, but reserve for most severe cases due to side effects. 3, 8

• Do not prescribe codeine or pholcodine, as they have no greater efficacy than dextromethorphan but significantly worse side effect profiles (drowsiness, nausea, constipation, physical dependence). 4, 8

Special Population: Lung Cancer Patients

• Treat underlying cancer first with surgery (stages I-II), radiation, or chemotherapy (stages III-IV), as this often resolves cough. 1

• For persistent cough despite cancer treatment, perform comprehensive assessment to identify treatable co-existing causes (pleural effusion, infection, COPD, GERD, UACS). 1

• Prescribe centrally acting cough suppressants (dihydrocodeine or hydrocodone) for symptomatic relief in lung cancer patients. 1

• Consider endobronchial brachytherapy for localized endobronchial disease causing cough. 3

Critical Pitfalls to Avoid

• Do not rely on cough characteristics (timing, quality, productivity) for diagnosis, as they have no predictive value for determining etiology. 1, 2, 3

• Do not treat only one cause and stop—multiple simultaneous causes are present in 59% of chronic cough cases, requiring sequential and additive therapy. 1, 2, 3

• Do not prescribe combination cough preparations with multiple active ingredients, as they are not evidence-based. 9

• Do not assume nocturnal cough indicates psychogenic or habit cough, as this is diagnostically unreliable. 2

• Do not continue benzonatate or other suppressants beyond 2-3 weeks without reassessing for alternative diagnoses. 4

• Do not use standard OTC doses of dextromethorphan (15-30 mg), as they are subtherapeutic; prescribe 60 mg for effective suppression. 4