Is Keflex (Cephalexin) 500mg every 6 hours for 10 days an appropriate treatment for an abscess?

Treatment of Abscess with Keflex (Cephalexin)

For an abscess, Keflex (cephalexin) 500 mg every 6 hours for 10 days is not the optimal treatment, as incision and drainage is the primary treatment for simple abscesses, with antibiotics generally not needed unless there are specific complicating factors. 1

Appropriate Management of Abscesses

Simple vs. Complex Abscesses

• Simple abscesses:

  • Incision and drainage alone is the primary treatment
  • Antibiotics are not needed if induration and erythema are limited to the defined area of the abscess 1
  • The 2018 WSES/SIS-E consensus states: "For a simple superficial abscess or boil, incision and drainage is the primary treatment, and antibiotics are not needed" 1

• Complex abscesses:

  • Require incision and drainage plus antibiotic therapy if:
    • Systemic signs of infection are present
    • Patient is immunocompromised
    • Source control is incomplete
    • Significant surrounding cellulitis exists 1

When Antibiotics Are Indicated

If antibiotics are needed (for complex abscesses), the recommendations are:

1. Empiric broad-spectrum coverage including Gram-positive, Gram-negative, and anaerobic bacteria 1

2. Duration of therapy:

   • For skin and soft tissue infections: 10-14 days typically recommended 2
   • For more severe infections: Consider longer duration (2-4 weeks) if there is delayed response 2

3. Antibiotic options when treatment is indicated:

   • For MRSA coverage (if suspected): Trimethoprim-sulfamethoxazole, clindamycin, or linezolid 2
   • For streptococcal coverage: Cephalexin is appropriate, but may not be sufficient alone if MRSA is suspected 2

Keflex (Cephalexin) Considerations

While cephalexin 500 mg every 6 hours for 10 days is an appropriate dosage according to the FDA label 3, research shows:

• A randomized, double-blind trial found that in abscesses where 87.8% of isolates were MRSA, the cure rate was 90.5% with placebo versus 84.1% with cephalexin after incision and drainage, suggesting antibiotics may be unnecessary after surgical drainage of uncomplicated abscesses 4

• Cephalexin is not adequate for MRSA coverage, which is commonly found in abscesses 2, 4

Clinical Algorithm for Abscess Management

1. Assess the abscess:

   • Determine if it's simple (well-defined, limited to a specific area) or complex (extensive cellulitis, systemic symptoms, immunocompromised host)

2. For simple abscesses:

   • Perform incision and drainage only
   • Antibiotics not needed 1

3. For complex abscesses:

   • Perform incision and drainage
   • Add antibiotics if:
     • Systemic signs of infection (fever, elevated WBC)
     • Immunocompromised patient
     • Incomplete source control
     • Significant surrounding cellulitis 1
   • Consider broader coverage than cephalexin alone if MRSA is suspected

Common Pitfalls to Avoid

1. Overuse of antibiotics for simple abscesses where incision and drainage alone is sufficient

2. Inadequate source control - surgical drainage is the cornerstone of treatment and antibiotics alone are insufficient

3. Inappropriate antibiotic selection - cephalexin lacks MRSA coverage, which is commonly found in abscesses

4. Failure to consider local resistance patterns - treatment should account for local prevalence of MRSA

In conclusion, while the dosing of Keflex (cephalexin) 500 mg every 6 hours for 10 days is appropriate according to the FDA label, antibiotics are generally unnecessary for simple abscesses after adequate incision and drainage. For complex abscesses requiring antibiotics, broader coverage may be needed if MRSA is suspected.