What antibiotic should be added to Augmentin (amoxicillin/clavulanate) to cover a cellulitis diagnosis in a patient with a urinary tract infection (UTI)?

Adding Antibiotic Coverage for Cellulitis in a Patient on Augmentin for UTI

For a 78-year-old female currently on Augmentin for UTI who has developed cellulitis of the right lower extremity, clindamycin should be added to provide appropriate coverage for skin and soft tissue infection.

Rationale for Adding Clindamycin

Augmentin (amoxicillin-clavulanate) is an appropriate choice for UTI treatment, but additional coverage is needed for cellulitis due to:

1. Clindamycin is specifically indicated for serious skin and soft tissue infections caused by susceptible strains of streptococci and staphylococci 1
2. Clindamycin provides excellent coverage against the common pathogens in cellulitis, including:
   • Streptococcus species
   • Staphylococcus aureus
   • Anaerobic bacteria that may be present in lower extremity infections

Dosing Recommendations

• Clindamycin: 300-450 mg orally three times daily for 5-6 days 2
• Continue the current Augmentin regimen for the UTI

Evidence Supporting This Approach

The American College of Emergency Physicians recommends broad-spectrum antibiotics for skin infections, with amoxicillin-clavulanate being a primary option 2. However, since the patient is already on Augmentin for UTI, adding clindamycin provides additional targeted coverage for the cellulitis.

Clindamycin is particularly effective against:

• Streptococci (common in cellulitis)
• Staphylococci (including some MRSA strains)
• Anaerobic bacteria (which may be present in lower extremity infections) 1

Important Considerations

Potential Pitfalls and Caveats

• Risk of C. difficile colitis: Monitor for diarrhea, which could indicate C. difficile infection, a known risk with clindamycin 1
• Allergies: Ensure the patient has no history of hypersensitivity to clindamycin
• Drug interactions: Check for potential interactions between clindamycin and the patient's other medications

Monitoring Recommendations

• Evaluate the patient within 24-48 hours to assess response to treatment 2
• Monitor for signs of worsening infection (increased pain, redness, swelling, or purulent discharge)
• Watch for signs of adverse drug reactions, particularly gastrointestinal symptoms

Alternative Options

If clindamycin is contraindicated or not tolerated:

1. Daptomycin could be considered for IV therapy, particularly if MRSA is suspected 3
2. Cephalexin (500 mg 3-4 times daily) is another alternative for skin and soft tissue infections 2

Special Considerations for Elderly Patients

For this 78-year-old patient:

• Start with lower doses if renal function is compromised
• Monitor more closely for adverse effects
• Consider shorter duration of therapy if good clinical response (5 days may be sufficient)
• Ensure adequate hydration to prevent kidney injury

By adding clindamycin to the current Augmentin regimen, you provide comprehensive coverage for both the UTI and cellulitis while targeting the most likely pathogens causing the skin infection.