What is the recommended first-line treatment for adults with respiratory infections?

First-Line Treatment for Adults with Respiratory Infections

For adults with respiratory infections, the first-line treatment should be determined based on the specific type of infection, severity, and patient risk factors, with amoxicillin being the recommended first choice for mild to moderate community-acquired pneumonia in outpatient settings. 1

Treatment Recommendations by Infection Type

Community-Acquired Pneumonia (CAP)

Outpatient Treatment (Mild to Moderate CAP):

• Oral amoxicillin 3 g/day is the recommended first-line treatment for suspected pneumococcal pneumonia, especially in adults over 40 years with or without underlying disease 1
• Oral macrolides (e.g., clarithromycin) are recommended for pneumonia suspected to be caused by "atypical" bacteria in adults under 40 years with no underlying disease, particularly in epidemic contexts 1, 2
• For patients at risk of drug-resistant Streptococcus pneumoniae, amoxicillin/clavulanate may be considered 3, 4

Hospitalized Patients (Moderate CAP without need for ICU):

• Treatment options include (in alphabetical order) 1:
  • Aminopenicillin ± macrolide
  • Aminopenicillin/β-lactamase inhibitor ± macrolide
  • Non-antipseudomonal cephalosporin
  • Cefotaxime or ceftriaxone ± macrolide
  • Levofloxacin
  • Moxifloxacin
  • Penicillin G ± macrolide

Severe CAP (ICU or Intermediate Care):

• For patients without risk factors for Pseudomonas aeruginosa 1:

  • Non-antipseudomonal cephalosporin III + macrolide, OR
  • Moxifloxacin or levofloxacin ± non-antipseudomonal cephalosporin III

• For patients with risk factors for Pseudomonas aeruginosa 1:

  • Antipseudomonal cephalosporin OR acylureidopenicillin/β-lactamase inhibitor OR carbapenem PLUS ciprofloxacin OR macrolide + aminoglycoside

Chronic Obstructive Pulmonary Disease (COPD) Exacerbations

• For mild exacerbations (usually managed at home) 1:

  • Amoxicillin or tetracycline
  • Alternatives: co-amoxiclav, macrolide, levofloxacin, or moxifloxacin

• For moderate-severe exacerbations without risk factors for P. aeruginosa 1:

  • Co-amoxiclav (oral)
  • Alternative: levofloxacin
  • For parenteral treatment: amoxicillin-clavulanate, second or third generation cephalosporin, levofloxacin, or moxifloxacin

• For moderate-severe COPD with risk factors for P. aeruginosa 1:

  • Ciprofloxacin (oral)
  • For parenteral treatment: ciprofloxacin or β-lactam with P. aeruginosa activity ± aminoglycosides

Acute Bronchitis

• Antibiotics are generally not recommended for acute bronchitis in healthy adults, as the clinical course is usually self-limiting within 10 days 1
• The benefit of antibiotic therapy on clinical course or prevention of complications has not been confirmed in clinical trials versus placebo 1

Aspiration Pneumonia

• For patients admitted to hospital ward from home 1:
  • Oral or IV β-lactam/β-lactamase inhibitor
  • Clindamycin
  • IV cephalosporin + oral metronidazole
  • Moxifloxacin

Administration Considerations

Route of Administration

• For ambulatory pneumonia, oral treatment can be used from the beginning 1
• For hospitalized patients, sequential treatment (IV to oral) should be considered in all patients except the most severely ill 1
• The switch from IV to oral should be guided by resolution of the most prominent clinical features at admission 1

Dosing for Common First-Line Agents

• Amoxicillin/clavulanate 5:

  • For respiratory infections: 875 mg/125 mg every 12 hours or 500 mg/125 mg every 8 hours
  • For more severe respiratory infections: 875 mg/125 mg every 12 hours or 500 mg/125 mg every 8 hours

• Clarithromycin extended-release 2:

  • Indicated for acute bacterial exacerbation of chronic bronchitis, acute maxillary sinusitis, and community-acquired pneumonia

Duration of Treatment

• For community-acquired pneumonia, treatment duration should generally not exceed 8 days in responding patients 1
• For pneumonia caused by intracellular pathogens such as Legionella spp., treatment should be for at least 14 days 1
• Biomarkers, particularly procalcitonin (PCT), may guide shorter treatment duration 1

Monitoring Response

• Response to treatment should be monitored using simple clinical criteria, including body temperature, respiratory, and hemodynamic parameters 1
• The same parameters should be used to determine suitability for hospital discharge 1
• Complete response, including radiographic resolution, requires longer time periods 1

Important Considerations

• Antibiotic resistance patterns should be considered when selecting therapy, particularly in areas with high prevalence of resistant S. pneumoniae 3, 4
• For patients with risk factors for P. aeruginosa (recent hospitalization, frequent antibiotic courses), specific antibiotic coverage is needed 1
• Early mobilization is recommended for all patients 1
• Low molecular weight heparin should be given to patients with acute respiratory failure 1
• Steroids are not recommended in the routine treatment of pneumonia 1