An 87-year-old patient who completed azithromycin (Z‑Pack) on Monday now has a persistent cough; what should I, as the primary care physician, do?

Reassess for Treatment Failure and Consider Alternative Diagnoses

In an 87-year-old patient with persistent cough after completing azithromycin, you should immediately reassess for pneumonia treatment failure, evaluate for alternative diagnoses including pertussis, and avoid simply repeating the same antibiotic without further workup.

Immediate Clinical Assessment

Your first priority is determining whether this represents:

• Treatment failure of pneumonia requiring different antibiotic coverage
• Post-infectious cough (which antibiotics won't help)
• Alternative diagnosis that was missed initially

Key Clinical Features to Evaluate Now

Assess for signs suggesting pneumonia 1:

• Fever ≥38°C (100.4°F)
• Breathlessness or dyspnea
• Tachycardia and tachypnea
• Crackles, diminished breath sounds on lung exam
• Abnormal vital signs

If any of these are present: This suggests treatment failure of pneumonia, not simple post-infectious cough.

Diagnostic Workup

For Suspected Pneumonia Treatment Failure:

1. Order chest X-ray if abnormal vital signs are present 1
2. Consider C-reactive protein (CRP) 1:
   • CRP ≥30 mg/L with symptoms increases pneumonia likelihood
   • CRP <10 mg/L makes pneumonia less likely
3. Do NOT routinely order procalcitonin 1

Critical Pitfall: Consider Pertussis

Pertussis can mimic refractory pneumonia in elderly adults without the classic "whooping" sound 2. This is especially important because:

• Azithromycin may fail due to macrolide resistance 2
• The patient may need trimethoprim-sulfamethoxazole instead 2
• Pertussis causes prolonged cough that won't respond to repeated macrolides

Management Algorithm

If Pneumonia is Confirmed or Strongly Suspected:

Switch antibiotic class - do not simply repeat azithromycin:

• Use a different antibiotic per local CAP guidelines (typically a respiratory fluoroquinolone or beta-lactam)
• Consider coverage for resistant organisms given treatment failure

If No Evidence of Active Pneumonia (Normal Vitals, Normal Lung Exam):

This is likely post-infectious cough 3:

1. Do NOT prescribe more antibiotics - they have no role in post-infectious cough 3

2. First-line treatment: Inhaled ipratropium bromide 3

   • This may attenuate the cough
   • Evidence level: Fair, Grade B recommendation

3. If ipratropium fails and cough severely affects quality of life:

   • Consider inhaled corticosteroids 3
   • Or short course of oral prednisone 30-40 mg daily, tapering over 2-3 weeks 3

Important Timing Consideration:

If cough persists beyond 8 weeks total, you must consider diagnoses other than post-infectious cough 3. At that point, evaluate for:

• Upper airway cough syndrome (post-nasal drip)
• Asthma or eosinophilic bronchitis
• Gastroesophageal reflux disease
• Chronic conditions 4

What NOT to Do

• Don't repeat azithromycin without confirming active bacterial infection - this promotes resistance and won't help post-infectious cough 3
• Don't assume it's "just a virus" in an 87-year-old without proper reassessment - treatment failure in elderly patients can deteriorate quickly
• Don't order routine microbiological testing unless results would change management 1

Bottom Line for This Patient

Given the age (87 years) and recurrence after initial improvement, perform a focused exam for pneumonia signs. If present, obtain chest X-ray and switch antibiotic class. If exam is reassuring, treat as post-infectious cough with ipratropium, explicitly counsel that more antibiotics won't help, and set expectation for gradual resolution over weeks.