What prescription is appropriate for a 75-year-old man with a three-week history of productive cough who now has influenza-like illness and nasal congestion?

Prescription for 75-Year-Old Man with 3-Week Productive Cough and Influenza-Like Illness

Do not prescribe antibiotics for the chronic cough component, but initiate oseltamivir 75 mg twice daily for 5 days for the acute influenza-like illness if symptoms began within the past 48 hours, along with symptomatic treatment for congestion.

Clinical Reasoning

The Chronic Cough (3 Weeks)

This represents acute bronchitis, which is almost always viral and self-limited. Antibiotics are strongly contraindicated 1. The evidence is clear: antibiotics provide no benefit for acute bronchitis and increase adverse events. One trial showed no difference in cough resolution between amoxicillin-clavulanic acid and placebo, while macrolides (azithromycin) caused significantly more adverse events than placebo 1.

The Acute Influenza Component

The new onset flu-like illness requires different management:

• If symptoms started ≤48 hours ago: Prescribe oseltamivir 75 mg orally twice daily for 5 days 2, 3, 4. At age 75, this patient is at high risk for severe complications. Evidence shows oseltamivir initiated within 48 hours reduces disease duration by up to 1.5 days, decreases severity by 38%, and significantly reduces secondary complications and antibiotic use 5. Most importantly, it reduces hospitalization risk in high-risk patients 2.

• If symptoms started >48 hours ago: The benefit of antivirals diminishes significantly, though some guidelines suggest considering treatment in high-risk elderly patients even beyond this window 4.

Symptomatic Management for Congestion

Provide symptomatic relief with:

• Decongestant: Phenylephrine or pseudoephedrine (check for contraindications like uncontrolled hypertension)
• Expectorant: Guaifenesin 200-400 mg every 4 hours as needed (up to 6 times daily) to help with sputum clearance 6
• Cough suppressant: Dextromethorphan for nighttime use if cough disrupts sleep 1
• First-generation antihistamine: Diphenhydramine for nighttime congestion relief (caution in elderly due to anticholinergic effects) 1

Critical Diagnostic Considerations

Before prescribing, you must rule out pneumonia 1, 2:

• Perform chest radiography if the patient has fever, tachypnea, focal chest findings, or appears systemically ill
• Consider C-reactive protein (CRP) if available—elevated levels strengthen pneumonia diagnosis 2
• If pneumonia is confirmed radiographically, then antibiotics ARE indicated

For influenza confirmation 3, 7:

• Ideally obtain nucleic acid amplification test (NAAT) or digital immunoassay (DIA) for diagnosis
• However, in high-risk patients during flu season with compatible symptoms, empiric treatment is reasonable while awaiting results

Common Pitfalls to Avoid

1. Do not prescribe antibiotics for bronchitis alone—this is the most common error and contributes to antimicrobial resistance 1
2. Do not use corticosteroids—conditionally recommended against in influenza 3, 4
3. Do not prescribe macrolides (azithromycin) as "coverage"—they increase adverse events without benefit in viral illness 1, 4
4. Do not use beta-agonists (albuterol) unless the patient has underlying asthma or COPD 1
5. Do not delay oseltamivir if within 48-hour window—earlier initiation yields better outcomes 2, 5

Sample Prescription

Rx 1: Oseltamivir 75 mg capsules

• Sig: Take 1 capsule by mouth twice daily for 5 days
• Disp: 10 capsules
• Note: Take with food to reduce nausea

Rx 2: Guaifenesin 400 mg tablets

• Sig: Take 1 tablet by mouth every 4 hours as needed for cough/congestion (maximum 6 times daily)
• Disp: 30 tablets

Rx 3: Dextromethorphan 30 mg capsules

• Sig: Take 1 capsule by mouth at bedtime as needed for cough
• Disp: 7 capsules

Over-the-counter recommendation: Pseudoephedrine 30-60 mg every 4-6 hours as needed for nasal congestion (if no contraindications)

Red Flags Requiring Reassessment

Return immediately or call if:

• Difficulty breathing or shortness of breath at rest
• Chest pain
• High fever (>39°C/102°F) persisting beyond 3 days on oseltamivir
• Confusion or altered mental status
• Inability to keep down fluids
• Worsening symptoms after initial improvement

These could indicate bacterial superinfection (requiring antibiotics) or progression to severe influenza requiring hospitalization 2.