Is cefepime (a fourth-generation cephalosporin) the same as ceftazidime (a third-generation cephalosporin)?

Cefepime vs. Ceftazidime: Different Cephalosporin Generations with Distinct Properties

No, cefepime is not the same as ceftazidime - they are different cephalosporins from different generations with distinct antimicrobial properties and clinical applications. 1

Key Differences

Classification and Generation

• Cefepime: Fourth-generation cephalosporin 1, 2
• Ceftazidime: Third-generation cephalosporin 1, 3

Antimicrobial Spectrum

• Cefepime:

  • Broader spectrum than third-generation cephalosporins 4
  • More active against Gram-positive bacteria 4
  • Effective against AmpC-producing organisms 1
  • Stable to hydrolysis by many plasmid and chromosomal beta-lactamases 4
  • Poor inducer of type I beta-lactamases 4

• Ceftazidime:

  • Particularly active against Pseudomonas aeruginosa (most active cephalosporin against P. aeruginosa when introduced) 3
  • Less active against Staphylococcus aureus than first and second-generation cephalosporins 3
  • Vulnerable to certain beta-lactamases that cefepime resists 4

Clinical Applications

Both antibiotics are used in similar clinical scenarios but with important differences:

• Hospital-acquired pneumonia:

  • Cefepime is recommended for low-risk mortality cases 1
  • Ceftazidime is specifically recommended when Pseudomonas aeruginosa infection is suspected 1

• Intra-abdominal infections:

  • Cefepime requires combination with metronidazole due to lack of anti-anaerobic activity 1
  • Ceftazidime also requires metronidazole for anaerobic coverage 1

• Febrile neutropenia:

  • Both are used as monotherapy options 1, 5
  • FDA-approved clinical trials directly compared cefepime monotherapy to ceftazidime monotherapy and found them therapeutically equivalent 5

Resistance Considerations

• Cefepime:

  • More stable against certain beta-lactamases 4
  • Better option for some ESBL-producing organisms 2
  • Current CLSI breakpoints for cefepime (≤ 8 μg/mL) do not identify all ESBL-producing strains 2

• Ceftazidime:

  • More vulnerable to resistance development 6
  • Current CLSI breakpoints for ceftazidime (≤ 4 μg/mL) do not identify all ESBL-producing strains 2

Clinical Implications of the Differences

• Cefepime has a lower potential for inducing resistance and selecting resistant mutants compared to third-generation cephalosporins like ceftazidime 6

• In areas with high prevalence of ESBL-producing Enterobacteriaceae, cefepime may retain activity against some strains resistant to ceftazidime 6

• For empiric therapy of serious infections, cefepime offers broader coverage against both Gram-positive and Gram-negative pathogens 4

Common Pitfalls and Caveats

1. Anaerobic coverage: Neither cefepime nor ceftazidime provides adequate anaerobic coverage, requiring combination with metronidazole for intra-abdominal infections 1

2. ESBL-producing organisms: Both antibiotics should generally be avoided for ESBL-producing organisms despite potential in vitro susceptibility, with carbapenems being preferred 2

3. Dosing differences: Cefepime is typically dosed twice daily in most indications, while ceftazidime is often dosed three times daily 4

4. Resistance development: Cefepime has a lower propensity for selection of resistant mutants compared to ceftazidime 6

In conclusion, while both antibiotics are cephalosporins used for similar indications, they represent different generations with distinct antimicrobial properties, resistance profiles, and specific clinical applications.