What are the recommended medication dosages for an adult patient with acute bronchitis and no known complicating medical history or allergies?

Acute Bronchitis Medication Dosing

For an otherwise healthy adult with acute bronchitis, antibiotics should NOT be prescribed routinely, as they provide minimal benefit (reducing cough by only half a day) while causing significant adverse effects. 1

Symptomatic Treatment (Primary Approach)

Antitussive Agents

• Dextromethorphan or codeine may provide modest relief for bothersome dry cough, especially when sleep is disturbed 2, 1
• These agents are occasionally useful for short-term symptomatic relief (Grade C recommendation) 2
• No specific dosing provided in guidelines, but standard over-the-counter formulations are appropriate 1

Bronchodilators (Limited Use)

• β2-agonist bronchodilators should NOT be routinely used in most patients with acute bronchitis 2, 3
• Exception: In select adults with wheezing accompanying the cough, β2-agonists may be useful 2, 3
  • Albuterol/salbutamol inhaler: 2-4 inhalations (200-400 μg) every 4 hours for mild episodes 3
  • For moderate episodes: 400 μg (4 inhalations) every 4 hours 3
• Adverse effects include tremor, nervousness, and shakiness 2, 4

Non-Pharmacologic Measures

• Elimination of environmental cough triggers and humidified air may provide benefit 1

When Antibiotics ARE Indicated

Confirmed or Suspected Pertussis (Whooping Cough)

• Macrolide antibiotic (erythromycin or azithromycin) should be prescribed 2, 1
• Erythromycin dosing: 250-333 mg orally four times daily for 10-14 days 2
• Isolate patient for 5 days from start of treatment 2, 1
• Early treatment (within first few weeks) diminishes coughing paroxysms and prevents disease spread 2, 1

Suspected Bacterial Superinfection (High-Risk Patients Only)

• Consider antibiotics only if fever persists beyond 3 days, suggesting bacterial superinfection 1
• High-risk patients include: elderly (>75 years), immunocompromised, or those with cardiac failure, insulin-dependent diabetes, or serious neurological disorders 1

If bacterial infection is confirmed or strongly suspected:

• Amoxicillin: 500 mg orally three times daily for 5-8 days 1
• Doxycycline: 100 mg orally twice daily for 1 day, then 100 mg once daily for 6-9 days 2, 1
• Trimethoprim-sulfamethoxazole: 160/800 mg orally twice daily for 7 days 2

What NOT to Use

• Expectorants and mucolytic agents are not recommended due to lack of consistent favorable effects 2
• NSAIDs at anti-inflammatory doses should not be used 1
• Systemic corticosteroids are not recommended 1
• Antihistamines have no proven benefit 1

Critical Clinical Pitfalls to Avoid

• Purulent sputum does NOT indicate bacterial infection - it occurs in 89-95% of viral cases and is not an indication for antibiotics 1, 5
• Duration of cough alone is not an indication for antibiotics - viral bronchitis cough typically lasts 10-14 days 1
• Rule out pneumonia first by checking for: heart rate >100 bpm, respiratory rate >24 breaths/min, fever >38°C, or focal chest findings (rales, egophony, fremitus) 2, 1
• Consider undiagnosed asthma - approximately one-third of patients diagnosed with acute bronchitis actually have asthma 1

Patient Education Points

• Inform patients that cough typically lasts 10-14 days after the visit, even without antibiotics 1
• Refer to the condition as a "chest cold" rather than "bronchitis" to reduce antibiotic expectations 1
• Explain that patient satisfaction depends more on physician-patient communication than whether antibiotics are prescribed 1
• Discuss risks of unnecessary antibiotic use, including side effects and antibiotic resistance 1

When to Reevaluate

• If fever persists >3 days: Consider bacterial superinfection or pneumonia 1
• If cough persists >3 weeks: Consider alternative diagnoses such as asthma, COPD, pertussis, or gastroesophageal reflux 1