What is the comparison between cefixime and co-amoxiclav (Augmentin) for treating infections?

Comparison of Cefixime and Co-amoxiclav

For most common infections, co-amoxiclav (amoxicillin-clavulanic acid) is the preferred choice over cefixime due to broader clinical utility, better coverage of resistant organisms including beta-lactamase-producing bacteria, and superior efficacy for respiratory tract infections and otitis media caused by Streptococcus pneumoniae.

Spectrum of Activity and Resistance Coverage

Co-amoxiclav provides superior coverage against beta-lactamase-producing organisms through the addition of clavulanic acid, which protects amoxicillin from enzymatic degradation 1. This is particularly important for:

• Staphylococcus aureus infections: Cefixime has minimal activity against S. aureus, while co-amoxiclav maintains good coverage 1
• Beta-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis: Both agents cover these organisms, though cefixime showed 100% eradication of H. influenzae in otitis media compared to 62% with amoxicillin alone 2
• Pseudomonas aeruginosa: Neither agent provides coverage 1

Respiratory Tract Infections

Co-amoxiclav demonstrates equivalent or superior efficacy for respiratory infections 1:

• For acute otitis media in children, cefixime showed 86.7% bacteriologic cure versus 79.4% with amoxicillin alone, though this difference was not statistically significant 2
• Critical caveat: When analyzing S. pneumoniae specifically (the most common otitis media pathogen), amoxicillin achieved 93.3% cure versus only 75% with cefixime 2
• All four treatment failures with cefixime in otitis media were S. pneumoniae cases 2
• For lower respiratory tract infections, cefixime showed comparable efficacy to amoxicillin-clavulanic acid 1

Urinary Tract Infections

Both agents show comparable efficacy for uncomplicated UTIs, but with important distinctions:

• For acute pyelonephritis, cefixime 400 mg once daily showed 97% clinical response versus 98% with amoxicillin plus netilmicin, with similar recurrence rates (16.9% vs 14%) 3
• In pediatric UTIs, cefixime demonstrated 100% bacterial susceptibility compared to only 69% for amoxicillin-clavulanate 4
• Cefixime offers the advantage of once-daily dosing due to its 3-hour elimination half-life 1

Gonorrhea Treatment (Historical Context)

Cefixime is no longer recommended as first-line therapy for gonorrhea due to rising resistance:

• The CDC now recommends against using cefixime routinely for gonorrhea, with cure rates of only 97.1-97.4% compared to 99.1% for ceftriaxone 5, 6
• Cefixime shows particularly poor efficacy for pharyngeal gonorrhea (approximately 91% cure rate) 6
• Rising minimum inhibitory concentrations have been documented, especially in the Western United States and among men who have sex with men 5, 6
• If cefixime must be used when ceftriaxone is unavailable, it requires combination with azithromycin 1 g orally and mandatory test-of-cure at 1 week 6

Dosing Convenience and Tolerability

Cefixime offers simplified dosing regimens:

• Once or twice daily administration versus three times daily for standard amoxicillin-clavulanate 1
• Both agents show similar rates of mild, self-limited gastrointestinal side effects (diarrhea, stool changes) 1, 2
• Tolerability is comparable between both drugs 3, 4, 2

Clinical Decision Algorithm

Choose co-amoxiclav when:

• Treating respiratory infections where S. pneumoniae is likely (otitis media, sinusitis, pneumonia) 2
• Staphylococcal coverage is needed 1
• Treating skin and soft tissue infections 1

Choose cefixime when:

• H. influenzae is the suspected pathogen in otitis media 2
• Once-daily dosing is critical for compliance 1, 3
• Treating uncomplicated UTIs in areas with high amoxicillin-clavulanate resistance 4
• Patient has documented allergy to penicillins (though cross-reactivity risk exists)

Common pitfall: Do not use cefixime for suspected S. pneumoniae infections, as failure rates are higher than with beta-lactam/beta-lactamase inhibitor combinations 2.