What are the primary uses of Cefixime (a third-generation cephalosporin antibiotic)?

Primary Uses of Cefixime

Cefixime is primarily used for uncomplicated urinary tract infections, otitis media, pharyngitis/tonsillitis, and acute exacerbations of chronic bronchitis, but should NOT be used as first-line therapy for gonorrhea due to rising resistance patterns. 1

FDA-Approved Indications

Urinary Tract Infections

• Cefixime 400 mg daily is indicated for uncomplicated UTIs caused by E. coli and Proteus mirabilis in adults and children ≥6 months. 1
• Clinical trials demonstrate 93% bacterial eradication rates in uncomplicated UTIs, with excellent efficacy particularly in female patients with acute uncomplicated cystitis (98% clinical effectiveness). 2
• For complicated UTIs, efficacy drops to 57-72% due to resistant gram-positive and non-fermenting organisms, making sensitivity testing mandatory before treatment. 3

Respiratory Tract Infections

• Approved for otitis media caused by H. influenzae, M. catarrhalis, and S. pyogenes (though efficacy for S. pneumoniae is approximately 10% lower than comparators). 1
• The suspension formulation must be used for otitis media, as it achieves higher peak blood levels than tablets/capsules at equivalent doses. 1
• Indicated for pharyngitis/tonsillitis caused by S. pyogenes, requiring at least 10 days of therapy, though penicillin remains the drug of choice. 1
• Approved for acute exacerbations of chronic bronchitis caused by S. pneumoniae and H. influenzae. 1

Gonorrhea: Critical Limitations

Current CDC Recommendations

• The CDC explicitly states that cefixime is NO LONGER recommended as routine first-line therapy for gonorrhea due to rising minimum inhibitory concentrations (MICs) and declining effectiveness. 4
• Cefixime 400 mg orally provides lower and less sustained bactericidal levels than ceftriaxone 125 mg IM, with cure rates of only 97.1-97.4% for urogenital/anorectal infections compared to 99.1% for ceftriaxone. 5, 6
• Cefixime demonstrates particularly limited efficacy for pharyngeal gonorrhea (approximately 91% cure rate), making it unsuitable for this site. 6

When Cefixime May Be Used for Gonorrhea

• Only as an alternative when ceftriaxone is unavailable: cefixime 400 mg orally PLUS azithromycin 1 g orally, with mandatory test-of-cure at 1 week. 4, 6
• Never use cefixime as monotherapy for gonorrhea due to resistance concerns. 6
• Resistance patterns are particularly concerning in the Western United States and among men who have sex with men (MSM), where elevated cefixime MICs increased from 0.2% in 2006 to 3.8% in 2011. 4, 5

Antimicrobial Spectrum

Organisms Covered

• Excellent activity against most Enterobacteriaceae (E. coli, Klebsiella, Proteus mirabilis), H. influenzae, M. catarrhalis, S. pyogenes, and N. gonorrhoeae (with noted resistance concerns). 7
• Inhibits 90% of common respiratory and urinary pathogens at concentrations ≤0.25-1.0 μg/mL. 7
• Stable against most common plasmid and chromosomal beta-lactamases. 7

Organisms NOT Covered

• No activity against enterococci, Listeria, Pseudomonas aeruginosa, Acinetobacter, Bacteroides species, or staphylococci. 7
• Poor activity against some strains of Enterobacter, Citrobacter freundii, and Morganella morganii. 7

Dosing Considerations

Adults

• Standard dose: 400 mg daily (may be given as single daily dose or divided). 1
• Can be administered without regard to food. 1

Pediatric Patients (≥6 months)

• 8 mg/kg/day of suspension, either as single daily dose or divided every 12 hours. 1
• Weight-based dosing ranges from 50 mg/day (5-7.5 kg) to 400 mg/day (>45 kg). 1

Renal Impairment

• Normal dosing for creatinine clearance ≥60 mL/min; dose adjustment required for lower clearances. 1
• Neither hemodialysis nor peritoneal dialysis removes significant drug amounts. 1

Common Pitfalls and Caveats

• Do not substitute tablets/capsules for suspension in otitis media treatment due to different pharmacokinetic profiles. 1
• Avoid empirical use in complicated UTIs without sensitivity testing, as resistant organisms are common. 3
• Never use for gonorrhea without azithromycin co-treatment and mandatory follow-up testing. 6
• Gastrointestinal adverse effects (diarrhea, stool changes) occur in up to 20% of patients, more common with once-daily 400 mg dosing versus twice-daily 200 mg dosing. 3, 8
• For S. pyogenes infections, maintain therapy for at least 10 days, though data on rheumatic fever prevention is lacking. 1