How should a cough be treated in patients with or without underlying respiratory conditions like COPD (Chronic Obstructive Pulmonary Disease) or asthma?

Cough Treatment

Start with a first-generation antihistamine-decongestant combination for chronic cough, as upper airway cough syndrome (UACS) is the most common cause, then sequentially add asthma treatment with inhaled corticosteroids plus beta-agonists, followed by high-dose proton pump inhibitors for GERD if cough persists—treating each cause additively since multiple etiologies frequently coexist. 1, 2

Immediate Actions Before Starting Treatment

• Stop ACE inhibitors immediately if the patient is taking one, as this is a reversible cause of chronic cough 1, 2, 3
• Counsel and assist with smoking cessation in current smokers, as smoking exacerbates cough and is a priority intervention 1, 2
• Rule out serious conditions such as pneumonia, pulmonary embolism, hemoptysis, or lung cancer through history and physical examination before initiating empiric therapy 1, 3, 4

Sequential Treatment Algorithm for Chronic Cough

Step 1: Treat Upper Airway Cough Syndrome (UACS) First

• Prescribe a first-generation antihistamine-decongestant combination as initial empiric therapy 1, 2
• Expected response time is days to 1-2 weeks 2
• Consider adding an intranasal corticosteroid spray to enhance upper airway control 2
• This addresses the most common cause of chronic cough and should be tried first even without definitive diagnostic testing 1

Step 2: Add Asthma/NAEB Treatment if Cough Persists

• Initiate combination inhaled corticosteroids plus beta-agonists if cough continues after treating UACS 1, 2
• Ideally perform bronchoprovocation challenge testing to confirm asthma, but if unavailable, proceed with empiric trial 1, 2
• Expected response time is up to 8 weeks 2
• Do not use albuterol alone for chronic cough not due to asthma 2
• Continue UACS treatment while adding asthma therapy, as multiple causes often coexist 1, 2

Step 3: Add GERD Treatment if Cough Still Persists

• Start high-dose proton pump inhibitor therapy with dietary modifications if cough remains despite treating UACS and asthma 1, 2
• GERD can cause cough even without typical gastrointestinal symptoms 2
• Expected response time is 2 weeks to several months 2
• Continue all previous treatments (UACS and asthma) while adding GERD therapy 2

Symptomatic Antitussive Therapy

For Acute Post-Viral or Post-Influenza Cough

• Dextromethorphan 60 mg provides maximum cough reflex suppression and prolonged relief, superior to standard over-the-counter doses of 15-30 mg which are subtherapeutic 3, 4
• Ipratropium bromide inhaler has the strongest evidence for attenuating post-infectious cough, with expected response time of 1-2 weeks 2, 5
• Honey with lemon may be effective for benign viral cough and should be considered before pharmacological treatments 3, 4
• Do not prescribe antibiotics for post-viral cough unless there is clear evidence of bacterial infection or suspected pertussis 4

For Chronic Cough in COPD or Chronic Bronchitis

• Central cough suppressants (codeine or dextromethorphan) are recommended for short-term symptomatic relief 2, 5
• However, a carefully conducted study showed codeine had no effect on cough in COPD patients 6, 7, so efficacy may be limited
• Success with opioid suppressants may require high doses associated with side effects 6, 7

For Idiopathic Chronic Cough (When All Treatments Fail)

• Low-dose morphine has been shown to be helpful in chronic idiopathic cough when other treatments fail 1, 3
• Alternative options include baclofen or nebulized local anesthetics (lidocaine, mepivacaine) under specialist guidance 1, 2
• Consider referral to a cough specialist if cough persists beyond 8 weeks despite appropriate sequential treatment 2

Special Considerations for Patients with Underlying Respiratory Disease

COPD Patients

• Optimize existing controller medications first before adding antitussive therapy 2
• Do not suppress productive cough in COPD when clearance is important 1
• Consider inhaled ipratropium bromide for symptomatic relief 2, 5
• Teach huffing techniques as an adjunct for sputum clearance 2

Asthma Patients

• Optimize inhaled corticosteroids if not already prescribed 2
• Combination therapy with inhaled corticosteroids and beta-agonists is recommended 2
• Medical history alone is unreliable for ruling in or out asthma as a cause of cough 1

Lung Cancer Patients

• Radiotherapy and both opioid and non-opioid antitussives have been recommended for symptomatic cough relief 1
• A 2015 trial showed neurokinin-1 receptor antagonist (aprepitant) significantly reduced cough counts in lung cancer patients, though this pathway requires further evaluation 1
• Future research should focus on cost-effective over-the-counter cough syrups containing dextromethorphan, glycerol, antihistamines, and guaifenesin 1

Critical Pitfalls to Avoid

• Never prescribe antibiotics for non-productive cough unless clear evidence of bacterial infection exists 4
• Do not use central cough suppressants for upper respiratory infection-related cough, as they have limited efficacy 2
• Avoid suppressing productive cough in pneumonia or bronchiectasis where clearance is important 1, 2
• Do not use codeine or pholcodine due to adverse effects and lack of greater efficacy than dextromethorphan 4
• Standard over-the-counter doses of dextromethorphan (15-30 mg) are subtherapeutic—use 60 mg for maximum effect 3, 4

When to Refer to Specialist

• Refer patients with persistent cough beyond 8 weeks despite systematically addressing UACS, asthma/NAEB, and GERD 2
• Consider high-resolution CT chest and bronchoscopy if all empiric therapies fail 2
• Specialist management may include low-dose morphine, baclofen, or nebulized local anesthetics for idiopathic chronic cough 1, 2

Red Flags Requiring Urgent Evaluation

• Hemoptysis (coughing up blood) requires urgent evaluation 3, 4
• Dyspnea (shortness of breath) requires urgent evaluation 3, 4
• Prolonged fever and general malaise require urgent evaluation 3, 4
• Symptoms persisting more than 3 weeks require reevaluation to rule out other causes 3, 4