What broad-spectrum antibiotics are used to treat cellulitis?

From the Guidelines

Broad-spectrum antibiotics commonly used to treat cellulitis include cephalexin, amoxicillin-clavulanate, clindamycin, and trimethoprim-sulfamethoxazole, with treatment typically continuing for 5-10 days, as recommended by the Infectious Diseases Society of America 1. The choice of antibiotic depends on the severity of the infection, suspected pathogens, and patient factors such as allergies and kidney function.

• For mild cases, oral antibiotics like cephalexin (500 mg four times daily) or amoxicillin-clavulanate (875/125 mg twice daily) may be sufficient.
• For more severe cases, intravenous therapy with ceftriaxone (1-2 g daily), cefazolin (1-2 g every 8 hours), or vancomycin (15-20 mg/kg every 12 hours) may be necessary.
• In areas with high MRSA prevalence, coverage should include antibiotics effective against resistant strains, such as vancomycin or linezolid, as recommended by the Infectious Diseases Society of America 1. It is essential to note that the duration of treatment may extend based on clinical response, and patients should complete the full course of antibiotics even if symptoms improve quickly.
• Elevation of the affected area and treatment of predisposing factors, such as edema or underlying cutaneous disorders, are also recommended 1.
• Outpatient therapy is recommended for patients who do not have systemic inflammatory response syndrome (SIRS), altered mental status, or hemodynamic instability, while hospitalization is recommended for more severe cases or patients with poor adherence to therapy 1.

From the FDA Drug Label

Clindamycin is indicated in the treatment of serious infections caused by susceptible anaerobic bacteria. Clindamycin is also indicated in the treatment of serious infections due to susceptible strains of streptococci, pneumococci, and staphylococci Adult patients with clinically documented complicated skin and skin structure infections were enrolled in a randomized, multi-center, double-blind, double-dummy trial comparing study medications administered IV followed by medications given orally for a total of 10 to 21 days of treatment. The cure rates in clinically evaluable patients were 90% in linezolid-treated patients and 85% in oxacillin-treated patients

The broad-spectrum antibiotics used to treat cellulitis include:

• Linezolid 2, with cure rates of 90% in clinically evaluable patients
• Clindamycin 3, which is indicated for the treatment of serious infections caused by susceptible anaerobic bacteria, streptococci, pneumococci, and staphylococci
• Oxacillin/Dicloxacillin 2, with cure rates of 85% in clinically evaluable patients
• Vancomycin 2, with cure rates of 73% in microbiologically evaluable patients with MRSA skin and skin structure infection
• Ampicillin/Sulbactam 2 and Amoxicillin/Clavulanate 2, with cure rates of 64% in the intent-to-treat population Note that the choice of antibiotic should be based on the suspected or confirmed causative pathogen and its susceptibility to the antibiotic.

From the Research

Broad-Spectrum Antibiotics for Cellulitis

• The following broad-spectrum antibiotics are used to treat cellulitis:
  • Cephalexin 4, 5, 6, 7
  • Clindamycin 4, 7
  • Trimethoprim-sulfamethoxazole 4, 7
  • Ceftriaxone 5, 8
  • Cefdinir 6

Comparison of Antibiotics

• A study compared the efficacy of cephalexin, trimethoprim-sulfamethoxazole, and clindamycin in treating cellulitis, and found that trimethoprim-sulfamethoxazole had a higher treatment success rate than cephalexin 4
• Another study compared ceftriaxone and cefazolin in treating skin and soft tissue infections, and found that they were equivalent in efficacy 5
• A study comparing cefdinir and cephalexin in treating mild to moderate uncomplicated skin and skin structure infections found that they had similar clinical cure rates 6

Considerations for Antibiotic Choice

• The choice of antibiotic should consider the likelihood of methicillin-resistant Staphylococcus aureus (MRSA) infection, as well as the severity of the cellulitis 4, 7
• Clindamycin and trimethoprim-sulfamethoxazole are effective against MRSA, while cephalexin is not 4, 7
• Ceftriaxone has been shown to be effective in treating skin and soft tissue infections, including those caused by multiple organisms 8