From the Guidelines
For cellulitis not responding to cephalexin alone, adding trimethoprim-sulfamethoxazole (TMP-SMX) is recommended, as supported by a randomized controlled trial comparing cephalexin plus TMP-SMX versus cephalexin alone for treatment of uncomplicated cellulitis 1. When considering a second antibiotic to add to cephalexin for cellulitis, the goal is to provide broader coverage against potential pathogens, including streptococci and staphylococci.
- Key considerations include:
- The severity of the infection
- Presence of risk factors such as diabetes or immunosuppression
- Suspected or confirmed methicillin-resistant Staphylococcus aureus (MRSA)
- According to the practice guidelines for the diagnosis and management of skin and soft tissue infections updated by the Infectious Diseases Society of America in 2014, combination therapy may be necessary for certain cases of cellulitis 1.
- The choice of TMP-SMX is based on its efficacy in combination with cephalexin, as demonstrated in clinical trials, and its coverage against MRSA, which is an important consideration in the treatment of cellulitis 1.
- Monitoring for clinical response and potential side effects is crucial, with adjustments to the treatment regimen made as necessary based on patient response and tolerance.
From the Research
Antibiotic Options for Cellulitis
When a patient is already on Cephalexin, the choice of a second antibiotic to add for cellulitis can be considered based on the following evidence:
- The studies 2, 3 suggest that adding trimethoprim-sulfamethoxazole to cephalexin does not significantly improve outcomes for uncomplicated cellulitis.
- However, the study 4 found that trimethoprim-sulfamethoxazole had a higher treatment success rate compared to cephalexin for outpatients with cellulitis, particularly in areas with a high prevalence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections.
- Another option to consider is clindamycin, as the study 4 found that it had higher success rates than cephalexin in patients with culture-confirmed MRSA infections, moderately severe cellulitis, and obesity.
- The network meta-analysis 5 found no significant differences in cure rates among various antibiotics for cellulitis, but identified ceftriaxone as having the fewest gastrointestinal side effects.
Key Findings
- Trimethoprim-sulfamethoxazole may be a suitable option to add to cephalexin for cellulitis, particularly in areas with high MRSA prevalence 4.
- Clindamycin may be considered for patients with MRSA infections, moderately severe cellulitis, or obesity 4.
- Ceftriaxone may be a good option due to its low risk of gastrointestinal side effects 5.