What is the best approach to manage a persistent cough in an elderly patient already taking Tessalon Perls (Benzonatate)?

Management of Persistent Cough in an Elderly Patient Already Taking Benzonatate

Since benzonatate alone is insufficient, you must systematically evaluate and treat the most common underlying causes of chronic cough rather than simply adding more cough suppressants. 1

Immediate Assessment Required

Before adding any therapy, determine:

• Is the patient taking an ACE inhibitor? If yes, discontinue it immediately—this is one of the most common reversible causes of chronic cough and should resolve within days to 2 weeks (median 26 days). 1

• Is the patient a current smoker? Smoking cessation should be the priority, as cough typically resolves within 4 weeks of quitting. 1

• Obtain a chest X-ray to exclude pneumonia, malignancy, heart failure, or other serious pathology before proceeding with empiric treatment. 1, 2

Systematic Treatment Algorithm

The three most common causes account for 85-100% of chronic cough in elderly patients: upper airway cough syndrome (UACS/postnasal drip), gastroesophageal reflux disease (GERD), and asthma/eosinophilic bronchitis. 3 You must treat these sequentially and additively, as multiple causes often coexist. 1

Step 1: Treat Upper Airway Cough Syndrome First

• Start a first-generation antihistamine/decongestant combination (e.g., diphenhydramine plus pseudoephedrine or similar). 1, 2
• If prominent upper airway symptoms exist, add topical nasal corticosteroids. 1
• Allow 2-4 weeks for response before moving to next step. 1

Step 2: Evaluate and Treat for Asthma/Eosinophilic Bronchitis

Cough may be the only manifestation of asthma—the medical history is unreliable for ruling it in or out. 1

• Perform spirometry if available; if normal, consider bronchial provocation testing if accessible. 1
• If testing unavailable or impractical, proceed with empiric trial: Inhaled corticosteroids plus bronchodilators (or add leukotriene receptor antagonist). 1, 2
• For severe or refractory cases, consider a 2-week trial of oral prednisone (30-40 mg daily)—if no response, eosinophilic airway inflammation is unlikely. 1, 2

Step 3: Treat GERD Aggressively

GERD is frequently overlooked and may cause cough without any gastrointestinal symptoms. 1

• Initiate high-dose proton pump inhibitor therapy plus alginates with strict dietary/lifestyle modifications. 1
• Treatment must continue for a minimum of 3 months—response is more variable than with UACS or asthma, ranging from 2 weeks to several months. 1
• If partial or no response, add a prokinetic agent (metoclopramide) and ensure rigorous adherence to dietary measures. 1

Maintain All Partially Effective Treatments

Because multiple causes frequently coexist, continue all therapies that provide even partial benefit while adding sequential treatments. 1 Do not discontinue one treatment when starting another unless it has clearly failed.

If Cough Persists After Above Steps

• Consider high-resolution CT scan to evaluate for bronchiectasis, interstitial lung disease, or occult airway pathology. 1
• Bronchoscopy may be warranted to exclude endobronchial tumor, sarcoidosis, or eosinophilic/lymphocytic bronchitis. 1
• Evaluate for less common causes: swallowing disorders (especially in elderly), congestive heart failure, or non-acid reflux disease. 1

Refractory Cough Management

If systematic treatment of all common causes fails:

• Consider neuromodulators: Low-dose gabapentin or pregabalin for refractory chronic cough. 2, 4, 5
• Speech pathology therapy with cough suppression techniques may be beneficial. 2
• Low-dose opiates (codeine or morphine) can be considered for symptom control when all else fails, particularly in palliative settings. 6, 2, 7
• Nebulized lidocaine has shown success in small studies for intractable cough, though evidence is limited. 8

Critical Pitfalls to Avoid

• Do not rely solely on benzonatate or add more cough suppressants without addressing underlying causes—this approach fails to improve morbidity or quality of life. 1, 2
• Do not treat only one potential cause—elderly patients frequently have multiple contributing factors. 3
• Do not give up on GERD treatment prematurely—it requires 3+ months and aggressive therapy including prokinetics. 1
• Do not assume cough characteristics have diagnostic value—they lack sensitivity and specificity. 1, 2

When to Refer to Specialist

Refer to a pulmonologist or specialized cough clinic if cough persists despite sequential trials of all common causes, or if diagnosis remains unclear after basic investigations. 1, 2