Are Levaquin (levofloxacin) and Flagyl (metronidazole) effective antibiotics for treating complicated skin infections?

Levofloxacin and Metronidazole for Complicated Skin Infections

The combination of Levaquin (levofloxacin) and Flagyl (metronidazole) is an effective treatment option for complicated skin infections, particularly when coverage for both aerobic and anaerobic pathogens is needed. 1

Rationale for This Combination

Complicated skin infections are typically polymicrobial, involving both aerobic and anaerobic bacteria. This combination provides:

• Levofloxacin: Effective against Gram-positive organisms (including methicillin-susceptible Staphylococcus aureus) and Gram-negative bacteria 2
• Metronidazole: Provides excellent coverage against anaerobic bacteria 1

According to the Infectious Diseases Society of America guidelines, fluoroquinolones (like levofloxacin) combined with metronidazole are specifically listed as appropriate treatment options for complicated skin and soft tissue infections 1.

Dosing Considerations

For complicated skin infections:

• Levofloxacin: 500-750 mg once daily 2, 3
• Metronidazole: 500 mg three times daily or 1500 mg once daily 1

Efficacy Evidence

Levofloxacin has demonstrated high efficacy in skin and soft tissue infections:

• Clinical success rates of 97.8-98% in uncomplicated skin infections 4, 5
• Bacteriological eradication rates of 97.5-98% 4, 5
• Particularly effective against Staphylococcus aureus with 100% eradication rate in one study 5

Treatment Algorithm

1. Assess infection severity:

   • Mild-moderate: Consider oral therapy
   • Severe: Begin with intravenous therapy with potential switch to oral 1

2. Consider local resistance patterns:

   • If high MRSA prevalence, add vancomycin or other MRSA-active agent 1, 6
   • If suspected Pseudomonas, higher doses of levofloxacin (750 mg) may be needed 3, 7

3. Duration of therapy:

   • Standard: 5-7 days for uncomplicated infections 8
   • Extended: 10-14 days for more severe infections 1

4. Monitoring:

   • Assess clinical response within 72 hours 8
   • If no improvement, consider surgical intervention or changing antibiotics 1

Special Considerations

• Surgical drainage is essential if an abscess is present 8
• Blood cultures should be obtained in patients with severe infection or systemic symptoms 8
• Treatment failure may indicate resistant organisms, inadequate source control, or deeper infection 1

Potential Limitations and Cautions

• Increasing fluoroquinolone resistance necessitates careful use and consideration of local resistance patterns 1, 7
• Not recommended as first-line therapy for uncomplicated skin infections 8
• Fluoroquinolones are contraindicated in children and adolescents under 18 years 8
• Consider alternative regimens in areas with high rates of fluoroquinolone resistance

Alternative Regimens

If levofloxacin and metronidazole cannot be used, consider:

• Piperacillin-tazobactam (for severe infections) 1
• Ampicillin-sulbactam 1
• Ertapenem (especially for ESBL-producing organisms) 1
• Cephalosporin plus metronidazole 1

The choice between these regimens should be guided by local resistance patterns, patient factors, and the suspected pathogens involved in the infection.