What oral antibiotics treat Pseudomonas (Pseudomonas aeruginosa) infections?

Oral Antibiotics for Pseudomonas Aeruginosa Infections

Ciprofloxacin and levofloxacin are the only reliable oral antibiotics for treating Pseudomonas aeruginosa infections, with ciprofloxacin 500mg twice daily being the preferred first-line option. 1

First-Line Oral Options

• Ciprofloxacin: 500mg twice daily 1, 2, 3

  • Most extensively studied oral agent against Pseudomonas
  • Clinical cure rates of 75% when used as monotherapy 2, 4
  • Preferred for respiratory and soft tissue infections

• Levofloxacin: 750mg once daily 1, 5

  • Equivalent activity to ciprofloxacin against Pseudomonas 6
  • Higher dose (750mg) required for adequate coverage 1
  • Better compliance with once-daily dosing 1

Treatment Selection Algorithm

1. Determine infection severity:

   • For mild-moderate infections: Oral therapy appropriate
   • For severe infections: Start with IV therapy, then transition to oral

2. Check local resistance patterns:

   • Fluoroquinolone resistance is increasing in many regions 1
   • Obtain cultures before starting therapy when possible 7

3. Consider infection site:

   • Respiratory tract: Ciprofloxacin preferred 7
   • Urinary tract: Either ciprofloxacin or levofloxacin 1

4. Evaluate patient risk factors:

   • For patients with risk factors for P. aeruginosa (recent hospitalization, frequent antibiotic use, severe lung disease, oral steroid use), ciprofloxacin is the first choice 7

Duration of Therapy

• Community-acquired pneumonia: 5-7 days 1
• Hospital-acquired pneumonia: 7-10 days 1
• Complicated infections: 10-14 days 1
• Chronic infections (e.g., bronchiectasis): 14+ days 7

Important Considerations

• Resistance development: Resistance can emerge during therapy, particularly when initial MICs are higher than 0.5 mg/L 4

• Combination therapy: For severe infections or in immunocompromised patients, oral therapy alone may be insufficient; consider IV therapy with combination antibiotics 8

• Cystic fibrosis/bronchiectasis: In these conditions, early treatment of intermittent colonization with a combination of systemic and inhaled antibiotics may delay chronic infection 7

• Monitoring: Follow clinical response and consider repeat cultures if improvement is not seen within 72 hours

Pitfalls to Avoid

• Underdosing: Always use high doses of fluoroquinolones for Pseudomonas infections (ciprofloxacin 500mg BID or levofloxacin 750mg daily) 1

• Monotherapy in severe infections: For severe infections, combination therapy may be more appropriate initially 8

• Prolonged therapy without clinical improvement: If no improvement after 72 hours, reassess and consider IV therapy or combination treatment

• Ignoring local resistance patterns: Local susceptibility patterns should guide therapy choices 7

• Inadequate duration: Pseudomonas infections typically require longer courses than other bacterial infections 7

Remember that while oral options exist for treating Pseudomonas infections, IV therapy may be necessary for severe infections, immunocompromised patients, or when oral therapy fails.